Asthma is a chronic disease that involves inflammation of the lungs. Airways swell and restrict airflow in and out of the lungs, making it hard to breathe. The word asthma comes from the Greek word for "panting." People with asthma pant and wheeze because they can't get enough air into their lungs.
Normally, when you breathe in something irritating, or you do something that causes you to need more air, like exercise, your airways relax and open. But with asthma, muscles in the airways tighten, and the lining of the air passages swells.
About 20 million Americans have asthma, including 9 million children. In fact, asthma is the most common chronic childhood illness. About half of all cases develop before the age of 10, and many children with asthma also have allergies.
Asthma can either be allergic or non-allergic. With allergic asthma, an allergic reaction to an inhaled irritant -- pet dander, pollen, dust mites -- triggers an attack. The immune system springs into action. But instead of helping, it causes inflammation. This is the most common form of asthma.
Non-allergic asthma does not involve the immune system. Attacks can be triggered by stress, anxiety, cold air, smoke, or a virus. Some people have symptoms only when they exercise, a condition known as exercise-induced asthma.
While there is no cure for asthma, it can be controlled. People with moderate-to-severe asthma should use conventional medications to help control symptoms. Complementary and alternative therapies, used under your doctor's supervision, may help, but shouldn't replace conventional treatment.
Signs and Symptoms
Most people with asthma go for periods of time without any symptoms, then have an asthma attack. Some people have chronic shortness of breath that gets worse during an attack. Asthma attacks can last minutes to days, and can become dangerous if airflow to the lungs becomes severely restricted.
Primary symptoms include:
- Shortness of breath.
- Wheezing, which usually begins suddenly. It may be worse at night or early in the morning. It can be made worse by cold air, exercise, and heartburn. Wheezing is relieved by using bronchodilators which are medicines that open the airways.
- Chest tightness.
- Cough (dry or with sputum). In cough-variant asthma, this may be the only symptom.
If you have any of these symptoms, seek emergency treatment:
- Extreme difficulty breathing or stopping breathing
- Bluish color to the lips and face, called cyanosis
- Severe anxiety
- Rapid pulse
- Excessive sweating
- Decreased level of consciousness, such as drowsiness or confusion
Asthma is most likely caused by several factors. Genes play a part. You're more likely to develop asthma if others in your family have it. Among those who are susceptible, being exposed to environmental factors, such as allergens, substances that cause an allergic reaction, or infections, may increase the chance of developing asthma.
The following factors may increase the risk of developing asthma:
- Having allergies.
- Family history of asthma or allergies.
- Being exposed to secondhand smoke.
- Having upper respiratory infections as an infant.
- Living in a large city.
- Gender. Among younger children, asthma develops twice as often in boys as in girls. But after puberty, it may be more common in girls.
- Gastroesophageal reflux (heartburn).
Childhood asthma, in particular, can be triggered by almost all of the same things that trigger allergies, such as:
- Dust, cockroach waste, pet dander, indoor and outdoor mold, and pollen.
- Air pollutants, such as smoke, perfumes, diesel particles, sulfur dioxide, high ozone levels, and fumes from paint, cleaning products, and gas stoves.
- Changes in the weather, especially in temperature (particularly cold) and humidity.
- Tobacco smoke.
- Aspirin and non-steroidal anti-inflammatory drugs (NSAIDs) can trigger asthma in up to 5% of adult asthma patients.
Other triggers include:
- Activities that affect breathing, such as exercising, laughing, crying, or yelling
- Stress and anxiety
Asthma symptoms can mimic several other conditions, and your doctor will take a thorough history to rule out other diseases. You may also have lung function tests to measure how much air your lungs can hold and how much air you breathe out. Your doctor may use a spirometer to measure how much air you exhale and how quickly you get air out of your lungs. Other tests may include chest and sinus x-rays, blood tests, or allergy tests.
Asthma is classified as:
- Mild intermittent: Having mild symptoms up to 2 days a week and 2 nights a month
- Mild persistent: Having symptoms more than 2 days a week but not more than 1 time in a single day
- Moderate persistent: Having symptoms once a day and more than 1 night per week
- Severe persistent: Having symptoms throughout the day on most days and often at night
Although you can't prevent asthma, you can take steps to reduce the number and frequency of attacks.
- Avoid allergens and irritants as much as possible. For example, reduce your exposure to dust mites by using special mattress and pillow covers that keep allergens out, and removing carpets from bedrooms. Clean your house frequently. Wear a mask while cleaning and choose cleaners without harsh chemicals.
- Exercise. Even people with exercise-induced asthma can stay active. And exercise will help you strengthen your lungs and maintain a proper weight. Take precautions when it's cold outside. Wear a face mask to warm the air that you breathe in. Talk to your doctor before starting an exercise regimen.
- Pay attention to your breathing. Watch for signs of an oncoming attack, such as wheezing. Your doctor may give you a machine called a peak flow meter that can detect slight differences in your breathing before you even notice them, so that you can take medication to ward off an attack. Your doctor will help you know which changes could mean you need medical attention right away.
- Treat attacks quickly. The sooner you treat an attack, the less severe it will be and the less medication you'll need.
- Consider immunotherapy (allergy shots). If you have allergies, allergy shots may lower the number of asthma attacks you have and their intensity, and also reduce the amount of medication you need. Immunotherapy includes regular injections of the substance you're allergic to, with each subsequent shot containing a slightly higher amount than the previous shot. Sublingual immunotherapy delivers the allergen in drops under the tongue. Over time your immune system becomes used to the allergen and no longer reacts to it. Talk to your doctor about whether immunotherapy is right for you.
Avoiding asthma attacks, reducing inflammation, and preventing lung damage are the primary goals of treatment. The more you know about your condition, the more closely you can work with your doctor to develop an asthma action plan. To control asthma, you need to prevent exposure to allergic triggers and take medication as prescribed. You may need emergency medications during an asthma attack. But monitoring your breathing and taking your medications every day will help you control asthma over the long term.
In a severe attack, you may need to be hospitalized for oxygen and medications that are given intravenously (IV).
- If you smoke, quit.
- Lose weight if you are overweight. Being overweight may put pressure on the lungs and trigger an inflammatory response.
- Monitor your condition every day using a peak flow meter, which is a portable device that helps measure how your lungs are working. Keep a diary of readings to show your doctor. Together, you will establish your "personal best" reading. You should call your doctor if your peak flow reading falls below 80% of your personal best. Go to the hospital if it falls below 50%.
- Keep a journal that logs changes or attacks. It may help determine triggers.
Medications for asthma are prescribed for two different purposes: to stop an immediate attack, and to control inflammation and reduce lung damage over the long-term.
Quick relief medications -- These drugs are called bronchodilators and help open the airways when you have an attack.
Short-acting beta-adrenergic agonists start working immediately. These drugs include:
- Albuterol (Proventil)
- Metaproterenol (Alupent)
- Pirbuterol (Maxair)
- Terbutaline (Brethaire)
- Levalbuterol (Xopenex)
Beta-adrenergic agonists may be used in combination with anticholinergic medications to treat severe asthma. Ipratropium bromide is the most commonly used anticholinergic drug for asthma treatment. Sometimes, steroids are needed for an acute asthma attack. They can take longer to work (from a couple of hours to a few days) and include:
Long-term control -- These drugs are usually taken every day.
Inhaled corticosteroids reduce inflammation and have fewer side effects than oral corticosteroids. They include:
- Beclamethasone (Qvar)
- Budesonide (Pulmicort)
- Flunisolide (Aerobid)
- Fluticasone (Flovent)
- Triamcinolone (Azmacort)
A class of drugs called leukotriene modifiers help reduce the production of inflammatory chemicals called leukotrienes that cause your airways to swell. They include:
- Montelukast (Singulair)
- Zafirlukast (Accolate)
Cromolyn (Intal), nedocromil (Tilade) -- These medications, which are inhaled, can help prevent mild-to-moderate attacks and are used to treat exercise-induced asthma.
Theophylline (TheoDur) -- This medication helps open airways and prevents asthma symptoms, especially at night. Too much can cause serious side effects. So your doctor will monitor levels in your blood.
Omalizumab (Xolair) -- Used to treat allergic asthma when other medications haven't worked.
A typical step-wise approach for long-term management of asthma might include low-dose inhaled corticosteroids, medium-dose inhaled corticosteroids, or low-dose inhaled corticosteroids plus long-acting beta-agonists, medium-dose inhaled corticosteroids plus long-acting beta-agonists, high-dose inhaled corticosteroids plus long-acting beta-agonists, and oral prednisone.
Nutrition and dietary supplements
Although there is no diet for asthma, people who have allergic asthma may also have food allergies that can make their asthma worse. If you think you may have food allergies, talk to your doctor about trying an elimination diet.
Eating plenty of fruits and vegetables that are high in antioxidants may also help you keep your asthma under better control. One study found that people with asthma who followed the Mediterranean diet had better control of asthma symptoms. Some studies have shown that people with asthma tend to have low levels of certain nutrients. But there is no evidence that taking supplements helps reduce asthma attacks. However, an overall healthy diet will help you get the nutrients you need and help your body deal with a long-term condition like asthma.
- Choline -- This B vitamin may help reduce the severity and frequency of asthma attacks. Some evidence indicates that higher doses (3 g per day for adults) may work better. But you should not take high doses without your doctor's supervision. More research is needed to say for sure whether choline helps.
- Magnesium -- The idea of using magnesium to treat asthma comes from the fact that people who have asthma often have low levels of magnesium. From some studies showing that intravenous (IV) magnesium can work as an emergency treatment for an asthma attack. However, studies that have looked at whether taking oral magnesium helped have shown mixed results. More research is needed.
- Fish oil -- The evidence for using omega-3 fatty acids (found in fish oil) to treat asthma is mixed. At least a few studies have found that fish oil supplements may reduce inflammation and symptoms in children and adults with asthma. But the studies have only included a small number of people. One study found that fish oil might make aspirin-induced asthma worse. Ask your doctor whether a high quality fish oil supplement makes sense for you. In high doses, fish oil may increase the risk of bleeding, especially if you take a blood thinner such as warfarin (Coumadin).
- Quercetin -- Quercetin, a kind of antioxidant called a flavonoid, helps to reduce the release of histamine and other allergic or inflammatory chemicals in the body. Histamine contributes to allergy symptoms, such as a runny nose, watery eyes, and hives. Because of that, quercetin has been proposed as a treatment for asthma. Quercetin can interact with certain medications. So ask your doctor before taking it.
- Vitamin C (1 g per day) -- One preliminary study suggested that children with asthma had significantly less wheezing when they ate a diet rich in fruits with vitamin C. Vitamin C does have anti-inflammatory and antioxidant properties, which may help you maintain good health overall. Some studies have indicated that taking a vitamin C supplement (1 g per day) may help keep airways open. But other studies have found no benefit.
- Coenzyme Q 10 (CoQ10) -- If you have asthma, you may have low levels of this antioxidant in your blood. However, researchers don't know whether taking CoQ10 supplements will make any difference in your asthma symptoms. CoQ10 may interfere with certain medications, including some chemotherapy agents and blood pressure medications. CoQ10 can increase the blood's clotting ability, interfering with blood-thinning medications such as warfarin (Coumadin) and aspirin, among others.
- Lycopene and beta-carotene -- preliminary data suggests that these two antioxidants, found in many fruits and vegetables, may help prevent exercise-induced asthma. People who smoke or take simvastatin (Zocor) should not take beta-carotene without talking to their doctors.
- Vitamin B6 -- Vitamin B6 may be needed if you are taking theophylline because this medication can lower blood levels of B6.
- Potassium -- Levels in the body may be lowered if you take theophylline.
The use of herbs is a time-honored approach to strengthening the body and treating disease. However, herbs can trigger side effects and interact with other herbs, supplements, or medications. For these reasons, you should take herbs with care, under the supervision of a knowledgeable health care practitioner.
- Boswellia (Boswellia serrata, 3 mg 3 times per day) -- Boswellia (also known as Salai guggal) is an herb commonly used in Ayurvedic medicine, a traditional Indian system of health care. In one study, people who took boswellia had fewer attacks and improved lung function. Boswellia may help leukotriene modifiers work better. However, more research is needed. People who take medication to lower their cholesterol, or people who take non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen (Advil, Motrin) should talk to their doctors before taking boswellia.
- Coleus forskohlii -- Coleus forskohlii, for forskolin, is another herb used in Ayurvedic medicine to treat asthma. Preliminary studies suggest that inhaled forskolin powder seemed to relieve symptoms. But more research is needed to know for sure. People who have diabetes or thyroid conditions should not take forskolin. If you take blood thinners, such as warfarin (Coumadin), taking forskolin may increase your risk of bleeding. Pregnant women should not take forskolin. Forskolin interacts with calcium channel blockers such as verapamil (Calan, Verelan), nifedipine (Procardia), and diltiazem (Cardizem, Dilacor), and with nitroglycerin (Nitro-Bid, Nitro-Dur, and Nitrostat), and isosorbide (Imdur, Isordil, and Sorbitrate).
- Tylophora (Tylophora indica, 250 mg 1 to 3 times per day) -- Tylophora has also been used historically to treat asthma. Scientific studies show that it can help reduce symptoms. But the studies were of poor quality. More research is needed. Tylophora may cause serious side effects at high doses, so talk to your doctor before taking it. Do not take tylophora if you are pregnant, have diabetes, high blood pressure, or congestive heart failure.
- Pycnogenol (Pinus pinaster, 1 mg per pound of body weight, up to 200 mg) -- A 2002 review of studies on a standardized extract from French maritime pine bark, called pycnogenol, suggests that it may reduce symptoms and improve lung function in people with asthma. Another study found that children with asthma who took pycnogenol along with prescription asthma medications had fewer symptoms and needed fewer rescue medications. Do not use pycnogenol if you have diabetes or take medication for high blood pressure. If you take blood thinners, such as warfarin (Coumadin), or aspirin, taking pycnogenol may increase your risk of bleeding.
- Saiboku-to -- In 3 preliminary studies, a traditional Japanese herbal mixture called Saiboku-to has helped reduce symptoms and allowed study participants to reduce doses of corticosteroids. In test tubes, Saiboku-to has shown anti-inflammatory effects. Saiboku-to contains several herbs, including Asian ginseng (Panax ginseng), Chinese skullcap (Baikal scutellaria), licorice (Glycyrrhiza glabra), and ginger (Zingiber officinale). These herbs can interact with other medications. So talk to your doctor before taking Saiboku-to.
Some preliminary studies indicate that acupuncture may help reduce symptoms for some people with asthma. But not all studies agree. Acupuncture should be used in addition to, not as a replacement for, conventional medicine when treating asthma.
Although few studies have examined the effectiveness of specific homeopathic therapies, professional homeopaths may consider the following remedies for the treatment of asthma based on their knowledge and experience. Before prescribing a remedy, homeopaths take into account your constitutional type -- your physical, emotional, and psychological makeup. An experienced homeopath assesses all of these factors when determining the most appropriate treatment for each individual.
Some people may find their symptoms get worse for a short time when starting on a homeopathic remedy. Because this may be dangerous for some people, be sure to work with a knowledgeable homeopath.
- Arsenicum album-- For asthma that generally worsens between midnight and 2 am and is accompanied by restlessness, anxiety, chills, and thirst.
- Ipecacuanha-- For those with asthma, particularly children, who have significant tightness in the chest, a chronic cough with lots of phlegm that may lead to vomiting, and worsening of symptoms in hot, humid weather.
- Pulsatilla-- For asthma with yellow or greenish phlegm that gets worse in the evening, in warm, stuffy rooms, or after consuming rich, fatty foods. This remedy is most appropriate for adults or children who are tearful and clingy, or sweet and affectionate.
- Sambucus-- For asthma that awakens a person at night with a sensation of suffocation. Symptoms worsen when the person is lying down.
Because stress and anxiety can make asthma worse, including stress management techniques in your daily life may help reduce symptoms. However, these techniques do not directly treat asthma.
- Hypnosis. This technique may be especially useful for children, who can easily learn the technique.
- Yoga. In addition to general relaxation and stress reduction, several studies of people with asthma have suggested that lung function improves with the regular practice of yoga. However, any benefits in breathing appear to be slight.
- Journaling. A study published in the New England Journal of Medicine documented the positive effect of daily journaling on people with asthma. Some people think that journaling allows for the release of pent-up emotions and helps reduce stress overall.
Clinical severity of asthma during pregnancy seems to follow severity before pregnancy. Exacerbations may occur in up to 36% of pregnancies, most frequently between 14 to 24 weeks.
Warnings and precautions
Long-term treatment with theophylline for asthma may reduce blood levels of vitamin B6.
Prognosis and complications
People with asthma can live normal, active lives. Because asthma is a chronic illness, it requires self-care and monitoring over the long-term, as well as continual communication with your doctor. Most people with asthma have occasional attacks separated by symptom-free periods. Paying attention to your mood, lowering the stress in your life, and having a good emotional support system will help you take good care of yourself. Routine follow-up visits are encouraged, at a frequency of every 1 to 6 months, depending on severity.
Aligne CA, Auinger P, Byrd RS, Weitzman M. Risk factors for pediatric asthma. Contributions of poverty, race, and urban residence. Am J Respir Crit Care Med. 2000;162(3 Pt 1):873-877.
Anandan C, Nurmatov U, Sheikh A. Omega 3 and 6 oils for primary prevention of allergic disease: systematic review and meta-analysis. Allergy. 2009 Jun;64(6):840-8. Epub 2009 Apr 7. Review.
Barros R, Moreira A, Fonseca J, et al. Adherence to the Mediterranean diet and fresh fruit intake are associated with improved asthma control. Allergy. 2008 Jul;63(7):917-23.
Biltagi MA, Baset AA, Bassiouny M, Kasrawi MA, Attia M. Omega-3 fatty acids, vitamin C and Zn supplementation in asthmatic children: a randomized self-controlled study. Acta Paediatr. 2009 Apr;98(4):737-42.
Birkel DA, Edgren L. Hatha yoga: improved vital capacity of college students. Altern Ther Health Med. 2000;6(6):55-63.
Burgess J, Abramson M, Gurrin L, et al. Childhood infections and the risk of asthma: a longitudinal study over 37 years. Chest. 2012; 142(3):647-54.
Burns JS, Dockery DW, Neas LM, Schwartz J, Coull BA, Raizenne M, Speizer FE. Low dietary nutrient intakes and respiratory health in adolescents. Chest. 2007 Jul;132(1):238-45. Epub 2007 May 2.
Bope & Kellerman. Conn's Current Therapy 2013, 1st ed. Philadelphia, PA: Saunders, An Imprint of Elsevier: 2012.
Chatzi L, Kogevinas M. Prenatal and childhood Mediterranean diet and the development of asthma and allergies in children. Public Health Nutr. 2009 Sep;12(9A):1629-34.
Chiang LC, Ma WF, Huang JL, Tseng LF, Hsueh KC. Effect of relaxation-breathing training on anxiety and asthma signs/symptoms of children with moderate-to-severe asthma: a randomized controlled trial. Int J Nurs Stud. 2009 Aug;46(8):1061-70.
Chipps B, Zeiger R, Borish L, et al. Key findings and clinical implications from The Epidemiology and Natural History of Asthma: Outcomes and Treatment Regimens (TENOR) study. J Allergy Clin Immunol. 2012; 130(2):332-42.e10.
Chu KA, Wu YC, Ting YM, Wang HC, Lu JY. Acupuncture therapy results in immediate bronchodilating effect in asthma patients. J Chin Med Assoc. 2007 Jul;70(7):265-8.
Ciarallo L, Brousseau D, Reinert S. Higher-dose intravenous magnesium therapy for children with moderate to severe acute asthma. Arch Ped Adol Med. 2000;154(10):979-983.
Ernst E. Breathing techniques -- adjunctive treatment modalities for asthma? A systematic review. Eur Respir J. 2000;15(5):969-972.
Fetterman JW Jr, Zdanowicz MM. Therapeutic potential of n-3 polyunsaturated fatty acids in disease. Am J Health Syst Pharm. 2009 Jul 1;66(13):1169-79.
Gazdol F, Gvozdjakova A, Nadvornikova R, et al. Decreased levels of coenzyme Q(10) in patients with bronchial asthma. Allergy. 2002;57(9):811-814.
Gdalevich M, Mimouni D, Mimouni M. Breast-feeding and the risk of bronchial asthma in childhood: a systematic review with meta-analysis of prospective studies. J Pediatr. 2001;139(2):261-266.
Gilliland FD, Berhane KT, Li YF, Kim DH, Margolis HG. Dietary magnesium, potassium, sodium, and children's lung function. Am J Epidemiol. 2002. 15;155(2):125-131.
Haby MM, Peat JK, Marks GB, Woolcock AJ, Leeder SR. Asthma in preschool children: prevalence and risk factors. Thorax. 2001;56(8):589-595.
Hackman RM, Stern JS, Gershwin ME. Hypnosis and asthma: a critical review. J Asthma. 2000;37(1):1-15.
Hijazi N, Abalkhail B, Seaton A. Diet and childhood asthma in a society in transition: a study in urban and rural Saudi Arabia. Thorax. 2000;55:775-779.
Huntley A, Ernst E. Herbal medicines for asthma: a systematic review. Thorax. 2000:Nov;55(11):925-9. Review.
Huntley A, White AR, Ernst E. Relaxation therapies for asthma: a systematic review. Thorax. 2002;57(20):127-131.
Joos S, Schott C, Zou H, Daniel V, Martin E. Immunomodulatory effects of acupuncture in the treatment of allergic asthma: a randomized controlled study. J Alt Comp Med. 2000;6(6), 519-525.
Kalliomaki M, Salminen S, Arvilommi H, Kero P, Koskinen P, Isolauri E. Probiotics in primary prevention of atopic disease: a randomized placebo controlled trial. Lancet. 2001;357(9262):1076-1079.
Kaur B, Rowe BH, Ram FS. Vitamin C supplementation for asthma (Cochrane Review). Cochrane Database Syst Rev. 2001;4:CD000993.
Lehrer P, Feldman J, Giardino N, Song HS, Schmaling K. Psychological aspects of asthma. J Consult Clin Psychol. 2002;70(3):691-711.
Levine M, Rumsey SC, Daruwala R, Park JB, Wang Y. Criteria and recommendations for vitamin C intake. JAMA. 1999;281(15):1415-1453.
Li XM. Traditional Chinese herbal remedies for asthma and food allergy. J Allergy Clin Immunol. 2007 Jul;120(1):25-31. Review.
Linde, K, Jobst K, Panton J. Acupuncture for chronic asthma (Cochrane Review). In: The Cochrane Library, Issue 3, 2001. Oxford: Update Software.
Mazur LJ, De Ybarrondo L, Miller J, Colasurdo G. Use of alternative and complementary therapies for pediatric asthma. Tex Med. 2001;97(6):64-68.
Mehta AK, Arora N, Gaur SN, Singh BP. Choline supplementation reduces oxidative stress in mouse model of allergic airway disease. Eur J Clin Invest. 2009 Jun 26. [Epub ahead of print].
Miller AL. The etiologies, pathophysiology, and alternative/complementary treatment of asthma. Altern Med Rev. 2001;6(1):20-47.
Nagakura T, Matsuda S, Shichijyo K, Sugimoto H, Hata K. Dietary supplementation with fish oil rich in omega-3 polyunsaturated fatty acids in children with bronchial asthma. Eur Resp J. 2000;16(5):861-865.
Nakao M, Muramoto Y, Hisadome M, Yamano N, Shoji M, Fukushima Y, et al. The effect of Shoseiryuto, a traditional Japanese medicine, on cytochrome P450s, N-acetyltransferase 2 and xanthine oxidase, in extensive or intermediate metabolizers of CYP2D6. Eur J Clin Pharmacol. 2007 Apr;63(4):345-53.
Neuman I, Nahum H, Ben-Amotz A. Reduction of exercise-induced asthma oxidative stress by lycopene, a natural antioxidant. Allergy. 2000;55(12):1184-1189.
Newnham DM. Asthma medications and their potential adverse effects in the elderly: recommendations for prescribing. Drug Saf. 2001;24(14):1065-1080.
Okamoto M, Misunobu F, Ashida K, Mifune T, Hosaki Y, Tsugeno H et al. Effects of dietary supplementation with n-3 fatty acids compared with n-6 fatty acids on bronchial asthma. Int Med. 2000;39(2):107-111.
Okamoto M, Misunobu F, Ashida K, et al. Effects of perilla seed oil supplementation on leukotriene generation by leucocytes in patients with asthma associated with lipometabolism. Int Arch Allergy Immunol. 2000;122(2):137-142.
Parker M. Asthma. Otolaryngologic Clinics of North America. W.B. Saunders Company. 2011;44(3).
Pascual R, Peters S. Asthma. Medical Clinics of North America. W.B. Saunders Company. 2011;95(6).
Raviv S, Smith LJ. Diet and asthma. Curr Opin Pulm Med. 2009 Sep 4. [Epub ahead of print].
Rohdewald P. A review of the French maritime pine bark extract (Pycnogenol), a herbal medication with a diverse clinical pharmacology. Int J Clin Pharmacol Ther. 2002;40(4):158-168.
Romieu I, Trenga C. Diet and obstructive lung diseases. Epidemiol Rev. 2001;23(2):268-287.
Rowe BH, Edmonds ML, Spooner CH, Camargo CA. Evidence-based treatments for acute asthma. [Review]. Respir Care. 2001;46(12):1380-1390.
Sathyaprabha TN, Murthy H, Murthy BT. Efficacy of naturopathy and yoga in bronchial asthma -- a self controlled matched scientific study. Ind J Physiol Pharmacol. 2001;45(10):80-86.
Shaheen SO, Newson RB, Rayman MP, Wong AP, Tumilty MK, Phillips JM, et al. Randomised, double blind, placebo-controlled trial of selenium supplementation in adult asthma. Thorax. 2007 Jun;62(6):483-90.
Shaheen SO, Sterne JA, Thompson RL, Songhurst CE, Margetts BM, Burney PG. Dietary antioxidants and asthma in adults: population-based case-control study. Am J Respir Crit Care Med. 2001;164(10 Pt 1):1823-1828.
Szefler S, Dakhama A. New insights into asthma pathogenesis and treatment. Curr Opin Immunol. 2011; 23(6):801-7.
Tamaoki J, Nakata J, Kawatani K, Tagaya E, Nagai A. Ginsenoside-induced relaxation of human bronchial smooth muscle via release of nitric oxide. Br J Pharmacol. 2000;130(8):1859-1864.
Urata Y, Yoshida S, Irie Y, et al. Treatment of asthma patients with herbal medicine TJ-96: a randomized controlled trial. Respir Med. 2002 Jun;96(6):469-474.
Ziment I, Tashkin DP. Alternative medicine for allergy and asthma. J Allergy Clin Immunol. 2000;106(4):603-614.