When looking for cold and flu products, it's really about choosing what makes you feel the best. Antibiotics are effective against bacteria but not against colds or the flu, which are caused by viruses. Antibiotic overuse has produced bacteria that are resistant to all known antibiotics, a serious public health threat. A study to be published in February 2000 found that Zicam zinc nasal spray shortened cold symptoms from almost 10 days to about three days. Try zinc lozenges after eating.
Many herbalists recommend goldenseal for flu.
Echinacea is also said to shorten symptoms when taken at the start of a cold or flu. But echinacea probably won't help if taken constantly over a long period of time. Doses of 500 mg four times a day may shorten cold symptoms by about a day or so. The jury is still out on whether vitamin C works as well for the flu as it does for colds. Flu can cause fever, and fever is dehydrating.