In 1940, George Rieveschl accepted a position in the Department of Chemical Engineering at the University of Cincinnati. Rieveschl embarked upon numerous research experiments, but his primary focus was on relieving muscle spasms. His research resulted in the discovery of Benadryl, an antihistamine used for allergy sufferers. Benadryl reduces the amount of Histamine in the human body, a chemical that causes allergy symptoms. Approved in 1946, Benadryl, at first, was available only through prescription.
The Parke, Davis & Company held the original patent for Benadryl. Rieveschl received five percent of the royalties from the sale of Benadryl as long as Parke, Davis & Company held the patent. Once the patent expired in 1964, Rieveschl's royalties ended, and other pharmaceutical companies began manufacturing the drug. During the 1980s, the Food and Drug Administration approved Benadryl for over-the-counter use. Allergy sufferers no longer needed a doctor's prescription to purchase the drug.