It’s the dirty little secret of the drug industry: That expiration date on your prescription or over the counter medications may be virtually meaningless.

An expiration date is required by the Federal Government and some states but drug experts say there is very little science to prove that these drugs are dangerous or even less effective if used beyond their expiration date. In fact, most drugs aren’t even tested for shelf life. One of the rare studies conducted found that 88 percent of drugs tested could be used past the expiration date for a period of 66 months or five and a half years! Some drugs can last even longer. According to the FDA, users of Amoxicillin, Ciprofloxacin, Diphenhydramine, and Morphine Sulfate injection can extend the life of their drugs anywhere from one year to 15 years.

The one exception experts told us about was Tetracycline. According to Lisa Gill of Consumer Reports, the antibiotic can become toxic if used after its expiration date. But even Gill says that for virtually every other drug it’s okay to keep them past their expiration date by as much as a year.

To extend the life of your drug, move it out of the medicine cabinet where humidity can hurt effectiveness. If you’re still nervous, stick to sell by dates on drugs you must absolutely have, like an Epi-pen, or heart medications and keep the Aspirin on the shelf longer than the label advises.