Do Medications Really Expire?

A few years ago I stumbled across and article about expiration dates on medicine, and whether they are still good past the date. Here's a link to the article, it's worth taking a look at.

http://www.rense.com/general29/fom.htm

Basically, the author says that, with a few exceptions, most medications are good for many years past their expiration date. They are not harmful, and at worst just start losing their potency. Nitroglycerin, insulin, and some liquid antibiotics are the main exceptions. If potency is important (like birth control pills or thyroid medication) it may be best not to let them go too far out of date.