The efficacy of four compounds was tested against Norway rat, Rattus norvegkus and roof rat, Rattus rattus akkaridrine4 under laboratory and field conditions. In both non-choice and free choice feeding tests, results proved that Oshar crude plant extract (10m1/ kg crushed maize) was the most effective one when extracted by chloroform or ethanol against both rat species followed by alphachloralose 2% (anaethetic) while L. histidine 0.005% (an amino acid) was the lowest effective one. In addition the data illustrated that Norway rat was more susceptible than roof rat for the all cases. Concerning the acceptance, L. histidine achieved the highest value followed by Oshar extracted by chloroform and ethanol, while the lowest value of acceptance was in case of alphachloralose for both tested species On the other way, the pathological changes on the different organs of the treated animals were studied. All the tested compounds caused obvious reduction for the body weight at different levels. In contrast, there were obvious increasing for the internal organs weight for the all cases. Sever cloudy and congestion were shown in liver and heart for all treatments except for L histidine who caused similar symptom slightly. Also, noticeable congestion was observed in kidney. Darkness of color occurred in spleen specially with Oshar treatment. Also, obvious congestic.1 and bleeding were observed on the lung in all cases. The field resifts were in harmony with the laboratory results as Oshar plant ethanolic extract was the most effective one. Whereas it gave the highest value of population reduction of rodent followed by Oshar extracted by chloroform while alphachloralose failed to achieve good reduction and the field performance of L. histidine was the less effective one.