yes I followed that link also. I was sad to discover that, however it is only the part about the onion being more poisonous than mayo that is false. The part about the flu and leaving an onion is actually true. Here is a one of several links that I found after I read the snopes article:
A few points to note on Onion Healing:
This is not a new idea. Onions were used by certain individuals in Europe to successfully fight off the plague in the early 1900’s. Ayurvedic medicine has been using an onion poultice for the chest or feet to cure coughs, fevers and flus for centuries. They also use the onion poultice to reduce pain and inflammation in the joints. Homeopathic doctors also use the healing power of onions to heal from viruses and illness. I even know people in the North American Hutterite community, a pacifist community similar to the Amish whose traditions date back to the 16th century, who tell me it is common practice to place onions in their homes during winter flu season and to use cut onions in the room of an ill person to relieve their symptoms quickly and naturally. Thanks @aunt-deb and yes I do always try my best to provide this community helpful useful information.
It is said that white onions work better than red onions. Yellow onions would be an acceptable alternative, but white onions, with the latin name Allium Cepa, work best.
I've heard of the poultices and it makes sense that something like that (especially in physical contact with the sick person) would have properties that heal. The fumes make mucus and phlegm easier to expel, thereby removing them from the system.
I just have a hard time buying the notion that onions are 'germ/disease magnets'. If that were the case, I think we'd see cut onions in every sickroom. But, if you think it works, go for it. I'll pass on this one.