Although Parke, Davis & Co. is no longer an independent corporation, it was once America's oldest and largest drug maker, and played an important role in medical history.

Dr. Duffield made a variety of pharmaceutical preparations, including Hoffman’s anodyne and mercurial ointment, but was overwhelmed by the operations of the business.

The company produced an herbal laxative drug Cascara found from Native Americans in the Pacific Northwest.

[5] In the case of Franklin v. Parke-Davis (2002), the company was accused of illegal marketing practices, including the promotion of off-label uses of its anticonvulsant medication Neurontin.

In 2004, Pfizer "admitted that Parke-Davis aggressively marketed Neurontin by illicit means for unrelated conditions including bipolar disorder, pain, migraine headaches, and drug and alcohol withdrawal", and consented to $430 million in penalties although it claimed the violations originated in 1996, well before Pfizer's acquisition of Warner–Lambert.

The ruling in favor of Parke-Davis by Judge Learned Hand is considered crucial to modern patent law.

The company promised that its cocaine products would "supply the place of food, make the coward brave, the silent eloquent and ... render the sufferer insensitive to pain."

"[11] Parke-Davis also was the original manufacturer and patent holder of phencyclidine (PCP) which is currently listed as a Schedule II drug in the United States.

Parke-Davis marketed the first widely available epilepsy treatment, Dilantin, which was approved in 1939, although it discovered neither the compound nor the application on its own.

Parke-Davis also produced the broad-spectrum antibiotic chloramphenicol, which was a blockbuster product before the discovery of its association with aplastic anemia.