Acetylsalicyclic acid sounds like a horrible way to die in a Breaking Bad episode, but it's just another name for aspirin.
The name aspirin in actually a trademark of the pharmaceutical conglomerate Bayer, but after World War II, those wily Americans decided not to accept the trademark registration, making the word aspirin a generic term. In European countries, however, it is still trademarked. Most folks there refer to aspirin as "ASA" for the chemical name of the substance.
Acetylsalocyclic acid is an analgesic and a non-steroidial anti-inflamatory drug (NSAID) designed to relieve pain. Originally found in the bark of the willow tree, Bayer was able to isolate the compound and produce it artificially. It also has an added benefit of preventing blood platelets from sticking together. For this reason, doctors sometimes prescribe low-dose aspirin to prevent stroke or to prevent further brain damage after a stroke.
Iron Noder 2017