Manufacturers guarantee product potency only until the expiration date. The medicine may be good later—but you can't be sure. Over-the-counter products in the original unopened manufacturers' packages kept under optimal conditions may last two years or more. Most prescription medicine is dispensed by pharmacists in patient-specific packaging and probably won't last as long.

Storage conditions also affect potency.

Example: If you keep medicine in a so-called medicine chest—a bathroom cabinet—it will degrade more quickly than if you store it away from bathroom heat and humidity.

Bottom line: After the expiration date, medicine should be discarded.

Want to Keep Reading?

Continue reading with a Health Confidential membership.

Sign up now Already have an account? Sign in