I don't know how many times per day I see random, incorrect, things posted to Facebook, but I happened to see one today that I just had to address it.

A friend of mine was tagged in a share from the Healthy Synonym Facebook page that shared an image of cut onions and the text,

DANGEROUS! Please remember it is dangerous to cut an onion and try to use it to cook next day, it becomes highly poisonous for even a single night and creates toxic bacteria which may cause adverse stomach infections because of excess bile secretions and even food poisoning. SHARE WITH EVERYONE!

Well, apparently nearly 150,000 people took that "share with everyone" in all caps at the end very seriously.

Here's the deal. This isn't true.

According to Snopes, this rumor has been going around since at least March of 2008.

The one instance we found that fingered bulb onions as the transmitter in a food poisoning case was the 1984 sickening of 28 people in Peoria, Illinois. Botulism was passed to those unfortunate souls by the sauteed onions used on a restaurant’s “patty melt”.

It's likely, Snopes says, that this belief came from the superstition that many believe wherein cut onions will pull toxins, germs, and bacteria from the air.