The intraperitoneal injection of sterile thioglycollate induces non-infectious peritonitis, with peritoneal exudates composed of neutrophils, lymphocytes and macrophages. Peritoneal leukocytosis elicited in C57BL/6 mice by thioglycollate challenge was significantly inhibited by the treatment with a 1 mg/kg i.p. bolus of zeatin riboside administered immediately after thioglycollate injection,