[yen223]

"This medicine is effective because it contains salicylic acid, which suppresses the activity of cyclooxygenase (COX), an enzyme that is responsible for the production of pro-inflammatory mediators."

versus

"This plant is effective because it's 100% natural!"

7 out of 10 times, people will go for the explanation that's easier to understand.

[aestra]

Salicylic acid is natural! It comes from the bark of the willow tree. It has been known since ancient times, presumably they used to consume willow bark. We then figured out the active ingredient in willow bark. However, asprin is acetylsalicylic acid, which is produced form salicylic acid to remove the side effects of salicylic acid.

[yen223]

I didn't choose that example by accident ;).

If I didn't know better, "salicylic acid" sounds like one of those chemicals that scientists keep putting in our food as part of their ongoing efforts to KILL ALL OF US, while "willow bark" sounds oh-so-natural and wholesome and makes me think of green meadows and chirping birds. So despite the fact that we know aspirin is a lot more effective than willow bark, I'd still feel a lot more comfortable eating willow bark. If I didn't know better.

Basically, evidence-based medicine faces a big marketing problem, thanks to the "evidence" part.