Nasal saline irrigation can reduce nasal congestion, sore throat, and cough. I suggest that my patients irrigate once a day or more often if needed.

Zinc lozenges might help decrease a cold’s duration. But I caution my patients that zinc has a metallic taste and too much can lead to copper deficiency.

The Natural Medicines Database tells doctors, “Remind people to throw away old recalled Zicam nasal products. Nasal zinc can cause a loss of smell.”

Adequate vitamin D levels are associated with a lower risk of respiratory infections. This looks promising, but it doesn’t prove that vitamin D prevents colds and flu. I try to remind people to get enough vitamin D … especially in the winter when there’s less sun.

Vitamin C is controversial. Some studies show it might help treat colds … but it doesn’t prevent them. The Natural Medicines Database says, “Warn patients the 1 to 3 grams per day used to treat colds can cause diarrhea.”

American ginseng (Cold-fX, etc) seems to SLIGHTLY reduce the severity or number of upper respiratory infections. About 1 in 4 people might get one fewer cold over 4 months.

For those of you on Coumadin (warfarin), keep in mind that American ginseng can decrease your INR.

Echinacea might modestly decrease a cold’s severity and duration in some people … but, like vitamin C, it doesn’t prevent colds. I advise people not to use it if they are allergic to ragweed – since cross reactions have been reported.

Elderberry might shorten flu symptoms by a few days. I recommend a product with some evidence of benefit such as Sambucol. You may also want to consider ViraBLOC.

Lactobacillus probiotics with or without Bifidobacterium might help decrease the number or severity of upper respiratory infections.

The Natural Medicines Database says, “Tell people not to depend on Airborne, Umcka ColdCare, astragalus, Asian ginseng, garlic, or oscillococcinum … there’s not convincing evidence that these will prevent or treat colds or flu.”

The Database also says, “Caution patients not to fall for internet scams promoting flu supplements. Warn high-risk patients not to rely on supplements, but to call (their doctor) promptly instead for possible (prescription) antiviral treatment.”