Tylenol is an extremely common and successful brand of pain relief medicine sold until very recently by Johnson & Johnson. The active ingredient is N-acetyl-para-aminophenol. This has been variously shortened to Acetaminophen, Paracetamol, or indeed Tylenol. Other medicines are sold under the Tylenol brand, such as Tylenol PM which is Acetaminophen and Dyphenhydramine (the drowsiness medication with a side effect of allergy relief that powers Benadryl and Sominex).