This study was conducted to evaluate the effect of Acetylsalicylic Acid (ASA) against the black rat, Rattus rattus, under laboratory and field conditions. ASA at 0.04 % mixed with crushed maize was tested as bait using non-choice and free-choice feeding tests. Moreover, the bleeding time was measured after different treatment periods, and the histopathology of some organs was studied as well. The efficiency of ASA bait was evaluated in clothes storage at El- Mansouria village, Giza Governorate. The laboratory results revealed that ASA bait achieved 80% mortality in non-choice feeding test and 60% mortality, with 48.5% acceptance, in free-choice feeding test. The bleeding time was enhanced after all treatment periods with different values. In addition, ASA bait caused severe histopathological changes in the tissues of some organs (brain, heart, lung, liver, kidney and ovaries). Regarding the efficiency of the ASA bait in the clothes storage, it achieved a 72% rat population reduction.  Therefore, ASA (0.04 %) bait can be used as a safe and cheap compound to reduce the rodent population in the fields.