http://www.latimes.com/health/boost...ugs-still-work-study-20121008,0,6591417.story NOTE: some antibiotics (tetracyclines) are toxic after expiry. http://www.survivalblog.com/2010/07/a_doctors_thoughts_on_antibiot.html
I'm a Certified Master Herbalist and I can tell you that many drugs will last past the expiration date, however, with drugs their effectiveness also decreases. That is not the case with Herbs. When considering health issues in a survival situation and other than that I would suggest herbs and colloidal minerals and vitamins as part of any survivalist or homesteader prep and the knowledge base on how to use them will be critical for survival.