Electron spin resonance spectroscopy was used to investigate the radiation damage in a powder of 2-acetoxybenzoic acid (Aspirin). Three types of radicals occur by gamma -irradiation of Aspirin at room temperature. Two of them are the result of hydrogen abstraction while the third is produced by hydrogen addition at one of the carbon atoms of the ring. The relative yielding of the free radicals as a function of absorbed dose in the range of 2.4 kGy to 160 kGy is also discussed.