Caffeine is widely consumed by the world population because its presence in major constitute of beverages like coffee and tea. This study was aimed at determining the biochemical effect on caffeine consumption in male wistar rats. This was a case-control study of the effect of exposing 180gram-220gram male wistar rats to caffeine for 3 days. Blood cortisol, FBG and FBC were measured in all the animals. Serum cortisol was significantly lower in the control group (P<0.001) and there was a significant weight loss in the caffeine-treated rats (P<0.001). Caffeine consumption had a significant direct correlation with weight (r-0.88 p<0.001). Similarly, increase cortisol level was significantly associated with increase in caffeine consumption (P>0.002).