The toxicosis of some non-steroidal anti-inflammatory drugs, piroxicam,indomethacin, phenylbutazone, and aspirin, which occasionally arelocally used in Nigeria as rodenticides have been evaluated in rats usingchanges in the serum biochemical and haematological parameters asindices of toxicity. In the study, no clinical symptoms were observed in allthe treatment groups except in the group of animals exposed toindomethacin which showed decreased feed intake, sluggishness,diarrhoea and some mortality were also recorded in the group. On theserum biochemical parameters, indomethacin and piroxicam causedincreases in the level of total bilirubin and decreases blood urea nitrogen.Aspirin, indomethacin, and phenylbutazone produced increases in serumaspartate aminotransferase and this increase is significant (P