Here here, JMG. I used to work in an institutional kitchen with a guy who had emigrated to the US from eastern Europe, and during cold and flu season he never got sick. His trick, which he said was common in his home country, was to peel a clove of fresh garlic in the morning after his shower, cut the garlic clove in half, and rub one half thoroughly on the instep of each foot, right below the ball of the foot. Garlic, of course, is full of allicin.

(Full disclosure: I never tried his remedy, since I had one of my own that worked quite well, but I don't doubt for a moment that it worked.)