A 6-year-old male tapir was admitted because it had been anorexic for 1 day. On admission, the tapir weighed 160 kg. Its rectal temperature was 32.4 degrees C, its heart rate was 120 beats per minute, and its respiratory rate was 12 breaths per minute. The elasticity of the skin was diminished. Haematological evaluation upon admission revealed a haematocrit of 0.63 L.L-1., 6.0 G.L-1 leucocytes with 40 per cent band neutrophils. The concentrations of urea nitrogen and creatinine in plasma were raised (18.9 mmol L-1. and 475 mumol L-1., respectively). Severe combined acidosis was apparent; the venous pH was 6.965, the bicarbonate concentration was 13.7 mmol.L-1., and the venous pCO2 was 8.6 kPa. No strongyle eggs were isolated from faeces by flotation, but a faecal sample yielded a positive culture for Pseudomonas aeruginosa. Urinalysis revealed proteinuria and the presence of leucocytes and renal epithelial cells. Treatment with fluids, TMP/S (17.5 and 3.5 mg/kg body weight, twice a day, respectively), and clenbuterol (0.56 microgram/kg body weight, twice a day) intravenously was unsuccessful and the tapir died 4 days after hospitalization. At necropsy, peritonitis due to a colon infarct as well as chronic bronchopneumonia and renal tubulonecrosis were found. The antibiotic susceptibility of the bacteria isolated (Streptoc. sp., E. coli, and K. pneumoniae) from the tapir post-mortem was assessed.