Perisoxal glucuronides were isolated from rabbit urine after repeated subcutaneous administration of dl-perisoxal citrate. Optical rotatory analysis of free bases obtained from the glucuronides indicated that about twice as much d-perisoxal glucuronide as l-isomer was formed. Stereoselective metabolism was observed in rabbit urine after d- or l-perisoxal administration. d-Perisoxal glucuronide was excreted predominantly at doses of 1.8 and 9.0 mg/kg. The excretions of d- and l-isomers of p-hydroxyperisoxal glucuronides were similar at the dose of 9.0 mg/kg, but a larger value was obtained for the l-isomer at the dose of 1.8 mg/kg.