What’s the Bottom Line?

What do we know about how complementary practices work for colds and flu?

• There’s no strong evidence supporting the use of any complementary health method to treat or prevent the flu.

• As for colds: Some techniques that may offer benefits include taking zinc by mouth, rinsing the nose and sinuses using a neti pot, using honey to ease night-time coughs in kids, trying meditation, taking probiotics, and using vitamin C during periods of heavy physical stress. However, the evidence for some other options—such as garlic, echinacea, and American ginseng—is inconsistent or doesn’t show clear results.

How safe are complementary methods for treating flu and colds?

• Improper use of nasal rinses can lead to serious infections if untreated tap water is used.

• Zinc-based nasal products have been linked to the loss of smell, which might be permanent.

• Regular use of supplements like probiotics or ginseng may pose risks, especially since long-term effects aren’t well understood.

• Safety varies from person to person. Age, health, pregnancy, and medications can all affect how safe a natural remedy is.

Understanding Flu and Colds

Each year, millions of Americans catch the common cold, and between 5% and 20% contract the flu. Although they share symptoms, the flu is typically more severe and may result in complications such as pneumonia. Colds generally remain mild.

There’s no vaccine to stop the common cold, but the flu can be prevented with annual vaccination for everyone 6 months and older. Getting vaccinated remains the most effective form of protection.

Antiviral medications can aid those who are very sick or vulnerable to complications, but they don’t take the place of flu shots. If you catch the flu, contact your doctor early to determine if antivirals are right for you—they work best when started promptly.

What Research Says About Flu and Complementary Health

To date, no alternative treatments have been proven to prevent the flu or ease its symptoms.

Several have been studied—including American ginseng, Chinese remedies, echinacea, elderberry, green tea, Oscillococcinum, and vitamins C and D—but none show definitive results.

Complementary Health Options for Colds: What We Know

American Ginseng

• Research has looked into whether American ginseng helps prevent colds. Some findings suggest it might shorten how long colds last, but not reduce how many colds people get.

• Long-term safety of this herb isn’t well studied. It may also interact with certain medications like blood thinners.

Echinacea

• Research on echinacea provides mixed results. A broad review found it hasn't been shown to significantly prevent or ease colds, although some products might have mild effects.

• There’s wide variety in echinacea products, which makes it hard to draw strong conclusions about its overall effectiveness.

• It’s usually well tolerated, but allergic reactions, including rashes in children, have occurred.

Garlic

• Current research doesn’t firmly establish whether garlic can prevent colds or lessen symptoms.

• Side effects may include body odor and digestive issues, and it may conflict with blood-thinning medications.

Honey

• Studies suggest honey can help reduce nighttime coughing in children.

• Avoid giving honey to babies under 1 year old due to the risk of botulism.

Meditation

• Stress reduction might lower the risk of colds. A study found that mindfulness meditation in older adults helped reduce the severity and duration of colds, more so than exercise or no intervention.

• While meditation is generally considered safe, those with serious medical or mental conditions should get medical advice first.

Probiotics

• Some research indicates probiotics could reduce the frequency and duration of colds. But the evidence quality is limited.

• Generally safe for healthy people, though long-term impact and risks for people with serious conditions remain uncertain.

Saline Nasal Rinses

• Rinsing your nose with salt water using devices like neti pots has shown limited success in easing cold symptoms.

• It’s vital to use treated or distilled water to avoid serious infections linked to contaminated tap water.

Vitamin C

• Studies show little prevention for the general public but possible benefits for those under intense physical stress.

• High doses may cause digestive problems. People with certain health conditions should consult doctors before use.

Zinc

• Oral forms like lozenges may shorten how long colds last if taken early. Some users have experienced side effects such as nausea and a metallic taste.

• Prolonged large doses can lead to health issues such as lowered immunity. Zinc also may interfere with medications like antibiotics.

• Nasal forms may cause loss of smell. Because of this risk, many intranasal zinc products have been removed from the market.

Additional Natural Options

Other remedies studied for colds include andrographis, various Chinese herbs, green tea, guided imagery, water therapy, and vitamins D and E. However, the evidence is still too limited to recommend them confidently.

Research Backed by NCCIH

Studies supported by NCCIH explore topics such as:

• Whether probiotics can improve older adults’ response to flu shots

• The impact of meditation and exercise on reducing respiratory illnesses

• How social connections affect vulnerability to colds

• The effects of echinacea on immune function

Important Considerations

• Natural remedies should not replace flu vaccination.

• Be sure to inform your doctors about any herbal products or alternative treatments you're using. This helps ensure your care is safe and coordinated.

Acknowledgments

Special thanks to contributors and experts from NCCIH and outside academic institutions who contributed to the development and periodic updates of this publication.

This document is in the public domain and may be freely copied and shared. It is intended for educational purposes and should not replace advice from a health care provider.