The first recorded outbreak of nephrotoxicosis induced by the shrub Nolletia gariepina is reported. The outbreaks occurred in cattle in the Kalahari sandveld of South Africa. The toxicosis was experimentally reproduced, initially in a steer, as a pilot trial to confirm toxicity of the plant material, and thereafter in two other cattle. Toxicity was induced by intraruminal administration of 3 g/kg dried, milled plant material as a single dose. The animals had to be starved for 24 hours before dosing, as dosing on a full rumen did not induce any signs of toxicity during five days of observation and clinical pathology monitoring. In both the field outbreaks and the experimental toxicological trial, clinical signs were not specific and varied according to the duration (acute versus subacute) of the toxicological process. Clinical pathological parameters in the experimental cases indicated renal and, to a lesser extent, hepatic damage, with raised serum concentrations of urea, creatinine, aspartate aminotransferase (AST) and gamma glutamyl transferase (GGT). Increased urinary sodium and potassium concentration and GGT activity, as well as proteinuria, were evident. The histological and electron microscopical examinations revealed acute renal tubular epithelial cell degeneration and necrosis, especially of the proximal convoluted tubules. Mild hepatocellular degeneration was also noticeable. / Dissertation (MMedVet (Pathology))--University of Pretoria, 2004. / Paraclinical Sciences / unrestricted