I worked for the company that first produced Preparation H. back in 1969, Sperti Drug Corporation. it is also a VERY effective Burn Ointment. The same product formulation was originally sold as "Sperti's Burn Ointment" If you have a burn immediately rinse it under cold water, dry the area and apply a thin film of ointment. be sure not to rub it off. Even if you can't treat the burn immediately it helps to put the ointment on ASAP. We also ran stability tests on this product and I can tell you that Biodyne is a very complex and STABILE molecule that will outlive the expiration date by years. Store in cool place or in a refrigerator for best long term longevity.