evidence: I know, people think that this must be an old wives remedy- and well, it is. But this is so effective that I have had many fall in love with this little secret, and years later, they will still write to me to tell me that the onion foot poultice has worked against another ugly illness for them. [...] Onion poultices are great for warding off almost any sickness that is trying to settle in such as colds and flus and any other viruses. You can use it in the very beginning or to try to get relief once the sickness has settled in. [...] Slice an onion horizontally and place the ring or half ring on the bottom of your foot. If you would like, you can wrap this with saran wrap to keep the smell in or to help hold heat in the feet. I personally prefer that my feet breathe, so I leave off the saranwrap. Then carefully pull your sock over to hold the onion slice in place on your foot.