Which medicines really came from rainforest plants, and how much is hype?

Rainforests have been called the "world's largest pharmacy", and that nickname comes with a big number attached. It is a slogan more than a count, so it is better to judge it story by story. Two of the best-documented stories are quinine and curare. Both were known to Indigenous peoples first, and both changed medicine.

Quinine comes from the bark of the cinchona tree, native to Peru. The Jesuit Agostino Salumbrino, an apothecary in Lima, saw the Quechua use the bark to treat shivering. The effect on shivering was unrelated to its effect on malaria, but the bark turned out to be a successful medicine against malaria, and he sent a little to Rome. Treating malaria with quinine is the first known use of a chemical compound against an infectious disease. A popular tale that a Countess of Chinchon brought it to Europe was disproven around 1941. In 1820 two French researchers isolated the pure chemical.

Curare is a name for various arrow poisons made from plant extracts that Indigenous peoples in Central and South America used for hunting. It blocks the signals that tell muscles to move, paralyzing them. In the 1800s Charles Waterton kept a curare-poisoned donkey alive with a bellows. In the 1940s doctors began using a standardized preparation to relax muscles during surgery.

Neither story is simple. Quinine is no longer the first-line malaria treatment because other drugs work equally well with fewer side effects. And curare has been replaced in the operating theatre by safer derivatives. The plants gave medicine a start, not always the final product.