Endo International plc is a generics and specialty branded pharmaceutical company. It was created as a result of a management buyout from DuPont Merck in 1997 led by Carol Ammon.

In 2009, Endo bought Indevus Pharmaceuticals to diversify into endocrinology and oncology. The company entered the male hypogonadism market later in 2010 with Fortesta 2% gel.

In November 2013, Endo agreed to purchase Paladin Labs Inc for about $1.6 billion to gain access to the Canadian market as well as expand into emerging markets.

In October 2014, Endo said it would buy Auxilium Pharmaceuticals for $2.6 billion.

In 2015, Endo acquired the specialty generics and sterile injectables company Par Pharmaceutical for $8.05 billion.

In early 2014, Endo sought to acquire NuPathe, a speciality pharmaceutical developer, for $105 million. However, Teva prevailed in this acquisition with a substantially higher bid.

Endo is one of the companies named in lawsuits by the states of Ohio, Missouri and Mississippi as responsible for the US opioid epidemic. Its 10-K statement indicates that a majority of the company's US revenue in 2016 was derived from the sale of prescription pain killers, predominantly opioids.

On June 8, 2017, the U.S. Food and Drug Administration (FDA) released a press statement in which it announced that it had request Endo to withdraw its opioid drug, oxymorphone hydrochloride (Opana ER), from the market. It was the first time that the FDA had "taken steps to remove a currently marketed opioid pain medication from sale due to the public health consequences of abuse."