Barr Pharmaceuticals was a global specialty and generic drug manufacturer with operations in 30 countries.

[4] Starting in 1991 Barr Laboratories was involved in a scandal stemming from their violation of GMP regulations concerning handling of out-of-specification (OOS) test results.

[7] In 1993, the company settled a patent infringement case and began distributing a generic version of tamoxifen citrate, a treatment for breast cancer.

[8] In 1995, the company received approval to manufacture and sell a generic version of zidovudine (AZT), a treatment for AIDS.

[9] In 1996, the company became the first to receive approval from the Food and Drug Administration to market generic Warfarin, which was previously only sold by DuPont.