Schering-Plough Corporation is a pharmaceutical company which traces its history back to 1851 when Ernst Schering founded Schering AG in Germany.

Following the entry of the United States into World War II in 1941, U.S. President Franklin Delano Roosevelt ordered Schering AG's U.S. assets be seized. These became Schering Corporation. The company was placed under a government administratorship until 1952, when it was released and its assets sold to the private sector. In 1971, the Schering Corporation merged with Plough to form Schering Plough.

Today Schering Plough manufactures several pharmaceutical drugs, the most well-known of which are the allergy drugs Claritin and Clarinex, and through a collaboration with Merck & Co., Zetia, an anti-cholesterol drug.

Schering Plough also owns and operates the major foot care brand name Dr. Scholl's and the skin care line Coppertone.

As of June 2005, Schering Plough has 1.4% market share in the U.S., placing it at #17 in the top 20 pharmaceutical corporations by sales compiled by IMS Health.

One of their plants, in Upper Hutt, New Zealand is the largest single site for the production of veterinary vaccines in the world. This is largely due to the fact that New Zealand's isolation has formed a natural quarantine and is free of rabies, foot and mouth, scrapie, bovine spongiform encephalopathy and many other livestock diseases. It formerly had echinococcosis, but this has been eradicated. The site is known locally as "Coopers Animal Health," a trademark still in use by Schering Plough in Australia, but not elsewhere.