6 March 1899: Aspirin trademarked

As early as the Ancient Egyptians, it was recognised that using the bark of the willow tree would help relieve minor aches and pains, including those caused by colds. However, it was not until 1763 that the medical community started to systematically investigate it, with the Royal Society publishing research into its role in treating fever.

The next major breakthrough came in 1828 when a professor at Munich University extracted the active ingredient from willow, named salicin. By 1876, further tests had shown that this was effective in reducing pain. During the late 19th century, salicylic acid became an increasingly used as a pain-relief drug. However, it has several unpleasant side effects, such as bleeding and nausea, which limited its use.

Chemical company Bayer set to work in 1895 to make a more palatable version of the drug. Two years later, Felix Hoffmann came up with acetylsalicylic acid. Initially, there was some scepticism about its effectiveness compared to other similar products. However, tests vindicated the new powder, which was trademarked by Bayer at 'Aspirin' on 6 March 1899. It appeared in tablet form in 1900 and became prescription-free in 1900.

By the 1950s, it would become the most widely sold painkiller. However, in 1974, research would suggest that it also plays an important role in preventing heart attacks. There is also strong evidence that it reduces the risk of cancer. At the moment, it is one of the top ten generic drugs in the world, with annual sales of around $1.64bn. However, Bayer's patent expired in 1917, meaning that generic competitors would get most of the profits.

Bayer would also lose the US rights to the name 'Aspirin' after it attempted to get around the wartime embargo on phenol, an important ingredient.