Colds are generally caused by virii. Killing the virii has been the best approach we have found to coping with a cold. Olive leaf extract, vitamin A and vitamin E are some of the natural antivirals I use when faced with a cold. I have also found that keeping my acidity under control makes me less likely to catch a cold in the first place. When I do get exposed to something (often at work), it helps to leave all our shoes by the front door in order to avoid tracking stuff into the house, and to shower as soon as I get home after a known exposure. Then I irrigate my sinuses, drink a little diet tonic water and take some supplements. I can usually clear up a cold within 12 hours of getting home from work.