By Julie Bromberg
Updated January 2013
Cold and flu are two of the most common illnesses and there is no “cure” for either. Antibiotics do not treat symptoms or cure either cold or flu. Many people turn to natural products to try to prevent and treat cold and flu symptoms. While some claim that products such as vitamin C or garlic have helped prevent illness or shorten the duration of the disease, there is often little scientific evidence to back up those claims. And, even if these products are natural, they are not necessarily safe.
The following tables compare products that people use to prevent or treat symptoms of cold and flu, and what research is able to tell us about the safety and effectiveness of these products.
Please note that some products are not meant to be used after symptoms begin. Instead you are supposed to take them everyday during the cold and flu season to boost your immune system. Many products are taken for 6-8 weeks, although some products can safely be taken for longer periods of time (such as ginger, garlic, and vitamin C).
Vitamins and Minerals
Herbal Products and Cold Symptoms
- Tell your doctor if you use any of these herbal products. Even though these are not considered “medicine,” they can be harmful to your health, especially when taken with certain prescribed medication.
- Studies of herbal products usually only test their effect on cold symptoms. Few studies have found that herbal products can prevent or treat the flu. The following information will mostly discuss the herbal product’s effect on cold symptoms, unless it explicitly states its effect on the flu.
- Doses listed in the label are for adults only, and recommended doses can vary widely. While some products have been tested on children, many do not identify a safe, effective dose for children. These dosing recommendations are based on commonly used doses in clinical trials, but recommended doses vary widely depending on the researcher and provider.
Most information is adapted from the following source, unless otherwise noted.
Kemper KJ. Complementary and Alternative Medicine Therapies for Cold and Flu Season: What Is the Science?: Natural Health Products. Medscape. November 3, 2009. Available at: http://www.medscape.com/viewarticle/711485_3
1 Office of Dietary Supplements, National Institutes of Health. Dietary Supplement Fact Sheet: Zinc. Accessed November 23, 2009. Available at: http://dietary-supplements.info.nih.gov/FactSheets/Zinc.asp#h3
2 Medline. Vitamin C. Accessed November 23, 2009. Available at: http://www.nlm.nih.gov/medlineplus/ency/article/002404.htm
3 National Academy of Sciences, Institute of Medicine. Food and Nutrition Board, Dietary Reference Intakes for Vitamin C, Vitamin E, Selenium, and Carotenoids. 2000.
4 Office of Dietary Supplements, National Institutes of Health. Dietary Supplement Fact Sheet: Vitamin D. Accessed November 23, 2009. Available at: http://dietary-supplements.info.nih.gov/factsheets/vitamind.asp
5 National Center for Complimentary and Alternative Medicine, National Institutes of Health. Get the Facts: An Introduction to Probiotics. August 2008. Accessed November 23, 2009. Available at: http://nccam.nih.gov/health/probiotics/#formore
6 Mayo Clinic. Drugs and Supplements: Ginseng (American ginseng, Asian ginseng, Chinese ginseng, Korean red ginseng, Panax ginseng: Panax spp., including P. ginseng C.C. Meyer and P. quinquefolius L., excluding Eleutherococcus senticosus), September 2009. Accessed December 7, 2009. Available at: http://www.mayoclinic.com/health/ginseng/NS_patient-ginseng/DSECTION=dosing
7 National Center for Complimentary and Alternative Medicine, National Institutes of Health. Fact Sheet: European Elder (Elderberry). April 2008. Accessed December 7, 2009. Available at: http://nccam.nih.gov/health/euroelder/
8 National Center for Complimentary and Alternative Medicine, National Institutes of Health. Fact Sheet: Echinacea. March 2008. Accessed February 3, 2010. Available at: http://nccam.nih.gov/health/echinacea/ataglance.htm
9 Medline Plus. Echinacea (Echinacea angustifolia DC, Echinacea pallida, Echinacea purpurea). August 2009. Accessed February 3, 2010. Available at: http://www.nlm.nih.gov/medlineplus/druginfo/natural/patient-echinacea.html#Dosing
10 Thompson Coon J & Ernst E. Andrographis paniculata in the Treatment of Upper Respiratory Tract Infections: A Systematic Review of Safety and Efficacy. Plant Medicine, 70(4): 293-298. 2004.
11 Lizogub VG, Riley DS, & Heger M. Efficacy of a pelargonium sidoides preparation in patients with the common cold: a randomized, double blind, placebo-controlled clinical trial. Explore: The Journal of Science and Healing, 3(6), 573-584. 2007.