Citrinin, a nephrotoxic mycotoxin, was dissolved in 0.5 N-NaOH neutralized with HCl and given in a single oral dose of 120 mg/kg (Trial I) or 80 or 100 mg/kg (Trial II) to male New Zealand white rabbits weighing 2.0-2.7 kg. In Trial I, sequential measurements of clinicopathological parameters were made over a 24-hr period. Azotaemia and metabolic acidosis with haemoconcentration and hypokalaemia developed within 4-12 hr. In Trial II, clinicopathological and urinary parameters were measured daily for 7 days. Increased blood urea nitrogen and serum-creatine levels and decreased creatinine clearance indicated renal failure; these values were most abnormal on days 2-4, returning to normal or near normal by day 7 in rabbits that survived. Urine analysis indicated tubular dysfunction and necrosis with glucosuria, isosthenuria and cylindruria; most urinary parameters were normal by day 7.