AbstractThe new xanthine derivative propentofylline (3‐methyl‐1‐[5′‐oxohexyl]‐7‐propylxanthine), administered intraperitoneally in a dose of 25 mg/kg 10 min before ligation of the left cerebral carotid artery in “sensitive” gerbils, improves the mean stroke index significantly at 4 and 24 hr postadministration. At a dose of 10 mg/kg, propentofylline improves the mean stroke index at all examined times (4, 24, and 72 hr), but at 5 mg/kg, a protective effect was obtained only after 24 hr. The mortality rate was lower in all propentofylline groups than in the control group. These results suggest that propentofylline is worth further study as a possible