Pharmacological and biochemical studies on the Ammi majus seeds L. (family Umbelliferae) grown in Egypt are limited. Furocoumarins are the major constituents in the plant seeds. In the present study, the evaluation of the antihyperlipidemic, anti-inflammatory, analgesic, and antipyretic activities on albino rats and mice was done. After 2 months of administration, both the doses (50 and 100 mg/kg body weight [bwt], respectively) of the alcoholic extract of the A. majus seed result in a significant decrease in the concentrations of cholesterol, triglycerides, and low-density lipoprotein and increase in the concentration of high-density lipoprotein. The extract was found to inhibit the rat paw edema at both the doses, which means that it exerts a significant anti-inflammatory activity compared with control-untreated groups at the intervals of 30 and 60 minutes posttreatment. The antipyretic effect of the extract was quite obvious; it showed that 100 mg/kg bwt was more potent in lowering body temperature starting after 1 hour of treatment than the lower dose (50 mg/kg bwt). It is worth to mention that the A. majus extract with its coumarin contents as well as the tested biological activities of the plant was investigated for the first time in the current study. In conclusion, ethanolic extract of the A. majus seeds had antihyperlipidemic, anti-inflammatory, analgesic, and antipyretic activities that are dose dependant.