A lot of people are convinced that zinc is good for colds - I'm agnostic, having not seen much convincing evidence - so if that's the case, why not snort zinc up your nose? That, at any rate, seems to be the condensed version of the Zicam pitch, although I don't believe that they used that exact wording in their ads. (A gift for advertising copy might not be one of my more robust talents. . .) At any rate, snorting zinc salts has actually been known, for some time now, to injure the sense of smell in some people. So it's proved with Zicam, with several hundred victims.
The moral? If you're going to sell homeopathic medicine - and boy, is it a lucrative business - make sure that you don't put anything in there except sterile water. That'll cut down on your expenses, too, since most ingredients cost more than water, anyway. Stick with that strategy, and you can be absolutely sure that nothing bad will happen to your customers. Nothing good will happen to them either, but they won't know that. When their cold/headache/whatever goes away of its own accord, they'll ascribe it to your miracle product. Sit back and profit! Be sure to thank Senator Hatch while you count your money, though - it's only proper.