Washington: Aspirin is among the most popular remedies used by people. Turns out some plants like it, too. Researchers at the National Center for Atmospheric Research were surprised to discover that stressed plants produce an aspirin-like chemical that can be detected in the air above the plants. The chemical may be a sort of immune response that helps protect the plants, the scientists said. Acetylsalicylic acid, or aspirin, was originally derived from tree bark, so scientists knew it was a compound made by plants. But it was never seen to be emitted as a gas. Such compounds can combine with industrial emissions to affect pollution and they can influence local climate. The trees were already stressed by drought, and levels of methyl salicylate rose with unseasonably cool night-time temperatures