Salicylic acid by Ray Sahelian, M.D.

Salicylic acid is a natural phenolic compound known as the active principle of aspirin.

Source of salicylic acid
This phenolic compound is found in fruits and vegetable. A high intake of produce can increase blood levels of salicylic acid. 

Benefit of salicylic acid
It is possible that the beneficial effects of regular fruit and vegetable consumption could be due to low chronic salicylic acid exposure.