The immune system is how the body protects itself from illness. It attacks the things that cause disease.
Healthy habits can help support the immune system. Natural therapies have also been used to support or strengthen the immune system.
- Andrographis is a plant that can be taken as a supplement. It is likely to quicken recovery and improve symptoms of colds and throat/chest problems. ( Note : It should not be taken by people who have problems with their immune system.)A6, A14, A20
- Echinacea is likely to reduce frequency and ease symptoms of some illnesses but is unlikely to reduce the frequency of common cold. ( Note : It should not be taken by people who have problems with their immune system, sleep, or anxiety.)A5, A8, A12, A15
- Flavonoids are compounds in food and drinks like wine and tea. They are likely to lower the rate of upper respiratory tract infections.A29
- L-arginine is an amino acid found in the body. It is likely to lower the rate of problems from infections.A32
- Pelargonium sidoides (African geranium) is a plant that can be taken as a pill, extract, lozenge, or syrup. It is likely to ease symptoms of cough and may reduce cold-like symptoms.A7, A9, A11, A23
- Traditional Chinese medicine is likely to have benefit in treating influenza.A30
- Zinc is an essential nutrient that can be taken as a pill, liquid, syrup, or lozenge. It is likely to shorten the time of illness and improve the outcome of colds and pneumonia. ( Note : It may cause nausea when used as a lozenge.)A10, A18, A19, A35
May Be Effective
May Not Be Effective
These therapies may not have benefit in treating the common cold:
Unlikely to Be Effective
Vitamin D is found in fish, milk, and sunlight. It is unlikely to have benefit.A28
Not Enough Data to Assess
Editorial process and description of evidence categories can be found at EBSCO NAT Editorial Process.
Herbs and Supplements to Be Used With Caution
Talk to your doctor about any supplements or therapy you would like to use. Some can interfere with treatment or make conditions worse, such as:
- Andrographis may make the immune system more active. Talk to your doctor before taking it if you have problems with your immune system. It may also not be safe to take with medication for sleep and anxiety.
- Echinacea should not be taken by people who have problems with their immune system, sleep, or anxiety.
- Zinc may cause nausea when used as a lozenge.
Herbs and Supplements
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A2. Meister R, Wittig T, et al. Efficacy and tolerability of myrtol standardized in long-term treatment of chronic bronchitis. A double-blind, placebo-controlled study. Study Group Investigators. Arzneimittelforschung.1999;49(4):351-358.
A3. Matthys H, de Mey C, et al. Efficacy and tolerability of myrtol standardized in acute bronchitis. A multi-centre, randomised, double-blind, placebo-controlled parallel group trial vs. cefuroxime and ambroxol. Arzneimittelforschung. 2000;50(8):700-711.
A4. Van Brummelen R, du Toit D. L-methionine as immune supportive supplement: a clinical evaluation. 2007;33(1):157-163.
A5. Schapowal A, Berger D, et al. Echinacea/sage of chlorhexidine/lidocaine for treating acute sore throats: a randomized double-blind trial. Eur J Med Res. 2009;14(9):406-412.
A6. Saxena RC, Singh R, et al. A randomized double blind placebo controlled clinical evaluation of extract of Andrographis paniculata (KalmCold) in patients with uncomplicated upper respiratory tract infection. Phytomedicine. 2010;17(3-4):178-185.
A7. Kamin W, Maydannik VG, et al. Efficacy and tolerability of Eps 7630 in patients (aged 6-18 years old) with acute bronchitis. Acta Paediatr. 2010;99(4):537-543.
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A9. Ross SM. African geranium (Eps 7630), part I: a proprietary root extract of Pelargonium sidoides (Eps 7630) is found to be effective in resolving symptoms associated with the common cold in adults. Holist Nurs Pract. 2012;26(2):106-109.
A10. Science M, Johnstone J, et al. Zinc for the treatment of the common cold: a systematic review and meta-analysis of randomized controlled trials. CMAJ. 2012;184(10):E551-561.
A11. Matthys H, Pliskevich DA, et al. Randomised, double-blind, placebo-controlled trial of Eps 7630 in adults with COPD. Respir Med. 2013; 107(5): 691-701.
A12. Karsch-Völk M, Barrett B, et al. Echinacea for preventing and treating the common cold. Cochrane Database Syst Rev. 2014;(2):CD000530.
A13. Lissiman E, Bhasale AL, et al. Garlic for the common cold. Cochrane Database Syst Rev. 2014;(11):CD006206.
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A16. Tiralongo E, Wee SS, et al. Elderberry Supplementation Reduces Cold Duration and Symptoms in Air-Travelers: A Randomized, Double-Blind Placebo-Controlled Clinical Trial. Nutrients. 2016;8(4):182.
A17. Nitsche MP, Carreño M. Is honey an effective treatment for acute cough in children? Medwave. 2016;16(2):e6454.
A18. Singh M, Das RR. Zinc for the common cold. Cochrane Database Syst Rev. 2013 Jun 18;(6):CD001364.
A19. Hemilä H, Petrus EJ, et al. Zinc acetate for treating the common cold: an individual patient data meta-analysis. Br J Clin Pharmacol. 2016;82(5):1393-1398.
A20. Hu XY, Wu RH, et al. Andrographis paniculate (Chuān Xīn Lián) for symptomatic relief of acute respiratory infections in adults and children: A systematic review and meta-analysis. PLoS One. 2017;12(8).
A21. Tshingani K, Donnen P, et al. Impact of Moringa oleifera Iam. Leaf powder supplementation versus nutritional counseling on the body mass index and immune response of HIV patients on antiretroviral therapy: a single-blind randomized control trial. BMC Complement Altern Med. 2017;17(1):420.
A22. Oduwole O, Udoh EE, et al. Honey for acute cough in children. Cochrane Database Syst Rev. 2018;4:CD007094.
A23. Riley DS, Lizogub VG, et al. Efficacy and Tolerability of High-dose Pelargonium Extract in Patients With the Common Cold. Altern Ther Health Med. 2018;24(2):16-26. A24. Hawkins J, Baker C, et al. Black elderberry (Sambucus nigra) supplementation effectively treats upper respiratory symptoms: A meta-analysis of randomized, controlled clinical trials. Complement Ther Med. 2019;42:361-365.
A24. Yoshino T, Arita R, et al. The use of maoto (Ma-Huang-Tang), a traditional Japanese Kampo medicine, to alleviate flu symptoms: a systematic review and meta-analysis. BMC Complement Altern Med. 2019 Mar 18;19(1):68.
A25. Quidel S, Gómez E, et al. What are the effects of vitamin C on the duration and severity of the common cold? Medwave. 2018 Oct 3;18(6):e7261.
A26. Gómez E, Quidel S, et al. Does vitamin C prevent the common cold? Medwave. 2018 Aug 6;18(4):e7235.
A27. Ran L, Zhao W, et al. Extra Dose of Vitamin C Based on a Daily Supplementation Shortens the Common Cold: A Meta-Analysis of 9 Randomized Controlled Trials. Biomed Res Int. 2018 Jul 5;2018:1837634.
A28. Yakoob MY, Salam RA, et al. Vitamin D supplementation for preventing infections in children under five years of age. Cochrane Database Syst Rev. 2016 Nov 9;11:CD008824.
A29. Somerville VS, Braakhuis AJ, et al. Effect of Flavonoids on Upper Respiratory Tract Infections and Immune Function: A Systematic Review and Meta-Analysis. Adv Nutr. 2016 May 16;7(3):488-497.
A30. Wang C, Wang H, et al. Traditional Chinese medicine for the treatment of influenza: a systematic review and meta-analysis of randomized controlled trials. J Tradit Chin Med. 2014 Oct;34(5):527-531.
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A32. Kang K, Shu XL, et al. Effect of L-arginine on immune function: a meta-analysis. Asia Pac J Clin Nutr. 2014;23(3):351-359.
A34. Chen W, Liu B, et al. Chinese patent medicines for the treatment of the common cold: a systematic review of randomized clinical trials. BMC Complement Altern Med. 2014 Jul 30;14:273.
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Last reviewed October 2019 by EBSCO NAT Review Board Eric Hurwitz, DC Last Updated: 6/1/2020