Allergan Plc engages in the research, development, and manufacture of pharmaceutical products. It operates through the following business segments: US Specialized Therapeutics; US General Medicine, and International. The US Specialized Therapeutics segment includes sales and expenses relating to branded products within the United States. The US General Medicine segment involves Central Nervous System; Gastrointestinal; Women's Health; Anti-Infectives; and Diversified brands. The International segment comprises of products sold outside the United States. The company was founded in 1984 and is headquartered in Dublin, Ireland.