Acetaminophen (also called paracetamol) was first synthesized in the late 1870s, and it began to be used as a medicine in people around the 1880s–1890s, with widespread therapeutic use taking off in the early 1950s.

Quick Scoop: Key Dates

  • 1877–1878: Chemist Harmon Northrop Morse synthesizes paracetamol (acetaminophen) by reducing p‑nitrophenol at Johns Hopkins University.
  • 1878 (often cited): The FDA and several histories describe acetaminophen as being “discovered” around this year in the context of coal-tar–derived pain relievers.
  • 1887–1893: German physician Joseph von Mering administers the drug to humans and reports its pain- and fever‑reducing effects, but it does not immediately become popular.
  • Late 1940s: Researchers (including Bernard Brodie and Julius Axelrod) show that paracetamol is a key, safer metabolite of older drugs like acetanilide and phenacetin, restarting interest in it.
  • Early 1950s: Acetaminophen finally enters routine therapeutic use as a safer alternative to older analgesics.
  • 1955–1956: It is launched as Tylenol in the United States (1955) and as Panadol in the UK (1956), which drives its global popularity.

So, “when was acetaminophen invented”?

If you’re looking for the invention date in the sense of first creation in a lab, most historians point to 1877–1878 for the first successful synthesis of acetaminophen/paracetamol. If you mean when it became a widely used medicine , that really begins in the early 1950s , capped by the launch of Tylenol in 1955.

You can think of it as a drug “invented” in the 1870s, almost forgotten, then “rediscovered” and turned into a household staple about 70 years later.

TL;DR: Acetaminophen was first synthesized in the late 1870s (around 1877–1878), but only became a common, widely marketed pain and fever medicine starting in the early 1950s.

Information gathered from public forums or data available on the internet and portrayed here.