Hippocrates advised about willow bark.
Quinine, a substance found in cinchona bark (from Peru), has a natural chemical that was known to ward off fevers, and especially malaria.
Parson Edmund Stone (in Cotswolds) reported his findings to the Royal Society of London in 1763.
In 1820s, Raffaele Piria, Italian chemist, isolated the chemical salicin from willow bark, and from it he made salicylic acid.
It was later discovered that this acid could also be extracted from the wild flower meadow-sweet (Spiraea ulmaria). Salicylic acid itself is a simple organic molecule made industrially from phenol and carbon dioxide.
It is from this plant that aspirin gets its name (a + spiraea), and the word was coined by the firm Bayer for the derivative, acetylsalicylic acid.
This had first been made around 1850 by a Frenchman, Charles Frederic Gerhardt, but although it was known to be a painkiller it burnt the mouth and stomach of those who tried it, and it tasted unpleasant. It later transpired that these side-effects were caused by impurities in the product.
In 1893, Felix Hoffmann and Henrich Dreser, chemists working for Bayer, found a way of purifying acetylsalicylic acid and obtained it as a white powder. It was taking the rouble for them, because by doing so they produced one of the most successful proprietary drugs ever made, and one considered safe enough to be sold directly to the public.
WARNING: In 1996, Americans swallow 50 million aspirin tablets a day, which is almost 20 billion a year. Aspirin is not risk-free and would not be passed for use under modern testing methods. Yesteryear methods of testings side-effects were lax and compromised then.
Aspirin causes stomach inflammation in some people, and it slowly reverts back to salicylic acid which is even worse. For this reason old aspirin tablets should never be taken.
Aspirin is regarded as more than just a painkiller. Then psychological advertisements indoctrinated the public thinking. At various times in the 100 years since it was first marketed it has been the standard treatment for virus infections (such as fevers, colds, and flu) and for arthritis (once commonly referred to as rheumatism).
Aspirin is a cure for none of these, it just makes them more bearable by reducing the aches and pains they cause. Aspirin is still bought and taken for these complaints under a variety of trade names, such as Anacin, Anadin, Aspro, Disprin, Ecotrin, Excedrin, etc., and of course as its best known version, Alka Seltzer. Nor is this plethora of names limited only to aspirin : it has become an integral part of the drug industry. (see the post on What's In a Name?)
Comprehend nature, then copy nature. Not alter nature.