A very interesting article. Rather dismissive to start off with, but stay with it. The action starts in the 'Comments' section with people who have actually tried it!
The onions and cold/flu remedy has been used in mainland Europe for centuries.
[Incidentally, the garlic (member of the onion family) and vampires legend has more than a grain of truth to it for the same reasons i.e. the absorbing of negative energies.
Using halved onions in a room is also used as psychic protection.]
If you do try this, afterwards, if it isn't already obvious, DO NOT EAT the onions. Bin them or preferably burn them.
Here is a site with some research done on onions:
Read the 'Comments' section to hear a different view from people who actually tried it...
Snopes or no Snopes, the fact that my body craves and loves onions and garlic tells me they are good foods. If this remedy works for some, it's a bargain, especially because it can do no harm.
We use a combination of 9 immune-building herbs (including garlic) for colds and 'flu, works so well it even eases tooth abscesses.