Do not throw away prescription and over-the-counter drugs just because they are past their expiration dates. These dates are not when the drugs will go bad—they are merely the dates beyond which the drugmakers no longer guarantee full potency. While there is a lot of variability among different drugs, drugmakers tend to be overly conservative with these potency guarantees because they don’t want to go to the expense of testing drug longevity over longer periods.

A 20-year Food and Drug Administration study found that 88% of the 122 medicines that were properly stored and tested still were perfectly fine a full year after their expiration dates, and the average expiration date could be extended by five-and-a-half years.

Expired drugs do not “spoil” as some expired foods do. There has not been a single confirmed case of an expired medication becoming toxic. The only potential risk from using an expired medication is that the drug might have lost some of its potency. A past-its-use-by-date pain medication might retain only 90% or 95% of its original potency, for example.

But using expired drugs is not worth the risk for lower potency when your life depends on the potency of the medication.

Examples: Replace your EpiPen when it reaches its expiration date if you have a potentially lethal allergy. Replace your nitroglycerine pills when they reach their expiration date if you have them for a serious heart condition.

Store medications in a cool, dry place out of direct sunlight. A bedroom drawer or kitchen cabinet can be a good spot (though not the kitchen cabinet above the stove). Do not store medications in the bathroom, where heat and humidity can reduce their useful life.

Medicine is especially likely to remain effective if it is in tablet or capsule form. Ointments, creams, liquid medications and any medications requiring refrigeration are significantly less likely to remain viable long after their expiration dates.