The effects of the chromatographic fractions of Euphorbia hirta Linn on the serum biochemical parameters in rats were investigated. The ethanolic extract of this plant was subjected to chromatographic separation using the vacuum liquid chromatographic technique, a modified form of classical column chromatography. With the aid of thin layer chromatography, six fractions of this plant were obtained and were administered to rats in graded doses of 400mg/kg, 800mg/kg and 1600mg/kg orally for fourteen days. Some fractions of this plant caused significant increase in the levels of total protein, albumin, globulin, alanine aminotransferase (ALT), alkaline phosphatase (ALP), aspartate aminotransferase (AST), total bilirubin, creatinine, and blood urea nitrogen (BUN). Some fractions also caused significant decrease in the level of conjugated bilirubin. The result from this study thus showed that some chromatographic fractions of Euphorbia hirta have potentially deleterious effects on the serum chemistry of rats; therefore caution should be exercised in the use of Euphorbia hirta as medicinal plant. It also means that the presence of this plant in the pasture could serve as a source of toxicosis to grazing animals.