Lol, you guys are funny. When I was a kid, vitamin C was the miracle cure for a cold. Then it was echinacea, Cold FX, zinc, and now everyone swears by oil of oregano.
I've tried them all, and IMO it's all just snake oil. Do nothing, and you're feeling better in a week; take the miracle pill and you're feeling better in seven days.
Having said that, I can't even remember the last time I was sick. It's been at least a year, maybe two. Hope I didn't just jinx myself.