Wasn't this on HN recently? Salicylic acid from willow bark has been known for millennia. But the side effects to the stomach are not good. Aspirin came along

Wasn't this on HN recently? Salicylic acid from willow bark has been known for millennia. But the side effects to the stomach are not good. Aspirin came along when enough was known about the chemistry to try to deal with the side effects. Aspirin is salicylic acid with an acetyl group hung on to reduce the side effects. Tweaking small molecule drugs to work better or have fewer side effects is common today. Aspirin was one of the first early successes.