Due to the decreasing efficacy and increasing contraindications of synthetic drugs, the use of natural drugs is on the rise and as a result, self-medication is very frequent. Citrus sinensis, of Asian and Indian origin is cultivated all around the world and use of its fruits as food and other parts for treatment of various illnesses is frequent in folk medicine. Acute oral toxicity study of the extracts of CP up to a dose of 5gKg-1BW was studied in mice. Sub-acute (aqueous and ethanol extract) and sub-chronic oral toxicity (aqueous only) were carried out in ratsat graded doses of 0.25gKg-1, .5gKg-1 and 1gKg-1 BW. Control groups received water and corn oil respectively. Assay for hematological, plasma biochemical parameters and histopathological examination were carried out. No signs of acute oral toxicity were recorded. Administration of the ethanol extract showed significant decreases in hematologic parameters and increases in animal body weight, liver, renal, lipid and glycemic parameters as well as vascular and inflammatory changes in liver and kidney, at high doses. The aqueous extract acted like an immune stimulator, with strong antioxidant activity while the ethanol extract presented the risk of artherosclerotic diseases and renal and liver malfunction
