I have been reading about placing onion on the soles of the feet to cure illness a lot lately. Actually this viral message has been circulating around for some time. Some say it is false while others say it works.
The idea is that placing sliced raw onions on the bottoms of one's feet and securing them with white socks before going to bed will "take away illness" overnight as the onions "absorb" toxins from the body. Some also say it prevents the flu. This turns out to be a relatively old folk remedy that was still being cited in home medical manuals of the late 1800s.