This study was carried out to determine the effects of ingested endotoxin on cellular and histological parameters in European albino rabbits - Oryctolagus cuniculus. Twenty-four (24) rabbits of either sexes weighing 1.5-1.8 kg each were randomly grouped into four of six (6) rabbits per group. The control group, A was orally administered with 5 % w/v dextrose containing 0 EU/ml and hence received 0 EU/kg body weight; groups B, C and D received 50, 500 and 1000 EU/kg body weight respectively, once daily by 10 am prior feeding for a total of 21 days. On a daily basis, blood samples were taken from each animal and serum levels of alanine transferase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP) and catalase activities; bilirubin, malondialdehyde, total protein, albumin (ALB), urea, uric acid and creatinine levels were assayed for. At the end of the 21 days a mortality of 20.83 % was recorded in the groups administered with endotoxin (500 and 1000 EU/kg bw). Also, there was significant increase (p <0.05) in the serum activities of ALT, AST and ALP; significantly reduced total protein and ALB levels with significant (p<0.05) increase in endotoxin doses and duration of the administration. There was significant increase (p<0.05) in bilirubin, urea and creatinine levels in the serum. Histopathology examinations show tissue degeneration in the liver, heart, kidney and lung related to increased dosages and durations of the orally administered endotoxin. We therefore conclude that oral ingestion of endotoxin causes damage to the liver, kidney, heart and the lungs in rabbits, especially when prolonged.