AbstractExperiments have been made with two sheep to determine their ability to synthesise hippuric acid. The titratable acidity of diethyl ether extracts of acidified urine was expressed as g benzoic acid equivalent. One sheep on a dried grass ration and one on a hay and oats ration excreted in the urine 8·06 and 4·07 g benzoic acid equivalent/24 h, respectively, the amounts conjugated with glycine being 2·63 and 2·38 g respectively. When non‐toxic levels of benzoic acid and glycine were infused into the abomasum, complete recovery of infused benzoic acid was obtained in terms of increased titratable acid in ether extracts of the urine. Infusion of 9·6 g of benzoic acid for 24 h as a continuous drip resulted in an increase of 11·89 g of benzoic acid equivalent in the urine, 8·90 g of which were conjugated with glycine. The largest non‐toxic dose given was 53·95 g of benzoic acid which gave rise to an increase in urinary benzoic acid equivalent of 58·47 g, 27·10 g of which were conjugated with glycine. Lethal doses for the two sheep were 1·1 and 1·8 g of benzoic acid/kg body weight. Urine collected during infusion of a toxic dose to one sheep contained a large increment in combined glucuronides. A very large increase in urinary potassium was observed in one sheep given a toxic dose of benzoic acid.