Merck KGaA is a German-based chemical and pharmaceutical company. Merck (also referred to as “German Merck” or “Merck Darmstadt”) was founded in Darmstadt, Germany, in 1668 and is one of the oldest still-operating chemical/pharmaceutical companies in the world. The company was privately owned until going public in 1995. However, the Merck family still controls a majority of the company's shares.

Following World War I, Merck lost possession of its foreign sites, including the Merck & Co. subsidiary in the United States. Merck & Co., called Merck Sharp and Dohme (MSD) outside the US and Canada, is now an independent company.

Merck KGaA operates mainly in Europe. Since Merck & Co. has rights to the Merck name in the US and Canada, the company operates under the umbrella brand EMD in North America, formed from the initials of Emanuel Merck, Darmstadt.