Walnut Trees Emit Aspirin-like Chemical To Deal With Stress

"Unlike humans, who are advised to take aspirin as a fever suppressant, plants have the ability to produce their own mix of aspirin-like chemicals, triggering the formation of proteins that boost their biochemical defenses and reduce injury," says NCAR scientist Thomas Karl, who led the study. "Our measurements show that significant amounts of the chemical can be detected in the atmosphere as plants respond to drought, unseasonable temperatures, or other stresses."

http://www.sciencedaily.com/releases/2008/09/080918170819.htm