What’s the Bottom Line?

What do we know about the effectiveness of complementary approaches for flu and colds?

  • No complementary health approach has been shown to be helpful for the flu.
  • For colds:
    • Complementary approaches that have shown some promise include oral zinc productsrinsing the nose and sinuses (with a neti pot or other device), honey (as a nighttime cough remedy for children), vitamin C (for people under severe physical stress), probiotics, and meditation.
    • Approaches for which the evidence is conflicting, inadequate, or mostly negative include vitamin C (for most people), echinaceagarlic, and American ginseng.

What do we know about the safety of complementary approaches for colds and flu?

  • People can get severe infections if they use neti pots or other nasal rinsing devices improperly. Tap water isn’t safe for use as a nasal rinse unless it has been filtered, treated, or processed in specific ways.
  • Zinc products used in the nose (such as nasal gels and swabs) have been linked to a long-lasting or even permanent loss of the sense of smell.
  • Using a dietary supplement to prevent colds often involves taking it for long periods of time. However, little is known about the long-term safety of some dietary supplements studied for prevention of colds, such as American ginseng and probiotics.
  • Complementary approaches that are safe for some people may not be safe for others. Your age, health, special circumstances (such as pregnancy), and medicines or supplements that you take may affect the safety of complementary approaches.

Some Basics About Flu and Colds

Each year, Americans get more than 1 billion colds, and between 5 and 20 percent of Americans get the flu. The two diseases have some symptoms in common, and both are caused by viruses. However, they are different conditions, and the flu is more severe. Unlike the flu, colds generally don’t cause serious complications, such as pneumonia, or lead to hospitalization.

No vaccine can protect you against the common cold, but vaccines can protect you against the flu. Everyone over the age of 6 months should be vaccinated against the flu each year. Vaccination is the best protection against getting the flu.

Prescription antiviral drugs may be used to treat the flu in people who are very ill or who are at high risk of flu complications. They’re not a substitute for getting vaccinated. Vaccination is the first line of defense against the flu; antivirals are the second. If you think you’ve caught the flu, you may want to check with your health care provider to see whether antiviral medicine is appropriate for you. Call promptly. The drugs work best if they’re used early in the illness.

To find out more about flu and colds, visit the National Institute of Allergy and Infectious Diseases Web site.

What the Science Says About Complementary Health Approaches for the Flu

No complementary approach has been shown to prevent the flu or relieve flu symptoms.

Complementary approaches that have been studied for the flu include the following. In all instances, there’s not enough evidence to show whether the approach is helpful.

  • American ginseng
  • Chinese herbal medicines
  • Echinacea
  • Elderberry
  • Green tea
  • Oscillococcinum
  • Vitamin C
  • Vitamin D

What the Science Says About Complementary Health Approaches for Colds

The following complementary health approaches have been studied for colds:

  • American Ginseng
  • Echinacea
  • Garlic
  • Honey
  • Meditation
  • Probiotics
  • Saline Nasal Irrigation
  • Vitamin C
  • Zinc

Other Complementary Approaches

In addition to the complementary approaches described above, several other approaches have been studied for colds. In all instances, there is insufficient evidence to show whether these approaches help to prevent colds or relieve cold symptoms.

  • Andrographis (Andrographis paniculata)
  • Chinese herbal medicines
  • Green tea
  • Guided imagery
  • Hydrotherapy
  • Vitamin D
  • Vitamin E

More to Consider

  • Complementary health approaches should never be used as a substitute for flu vaccination.
  • Tell all your health care providers about any complementary health approaches you use. Give them a full picture of what you do to manage your health. This will help ensure coordinated and safe care

For More Information

NCCIH Clearinghouse

The NCCIH Clearinghouse provides information on NCCIH and complementary and integrative health approaches, including publications and searches of Federal databases of scientific and medical literature. The Clearinghouse does not provide medical advice, treatment recommendations, or referrals to practitioners.

Toll-free in the U.S.:
1-888-644-6226
TTY (for deaf and hard-of-hearing callers):
1-866-464-3615

National Institute of Allergy and Infectious Diseases (NIAID)

NIAID conducts and supports research to study the causes of allergic, immunologic, and infectious diseases, and to develop better means of preventing, diagnosing, and treating these illnesses.

Toll-free in the U.S.:
1-866-284-4107

Flu.gov

Managed by the U.S. Department of Health and Human Services, Flu.gov provides comprehensive government-wide information on seasonal, H1N1 (swine), H5N1 (bird), and pandemic influenza for the general public, health professionals, and others.

PubMed®

A service of the National Library of Medicine, PubMed® contains publication information and (in most cases) brief summaries of articles from scientific and medical journals. For guidance from NCCIH on using PubMed, see How To Find Information About Complementary Health Approaches on PubMed.

MedlinePlus

To provide resources that help answer health questions, MedlinePlus (a service of the National Library of Medicine) brings together authoritative information from the National Institutes of Health as well as other Government agencies and health-related organizations.

Information on the common cold
Information on flu

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