Rats with artificial calculosis of one ureter develop hyperalgesia in the ipsilateral oblique musculature as evidenced by decreased vocalization threshold to electrical muscle stimulation lasting over a week. The aim of the study was to evaluate the effect on this hyperalgesia of spasmolytic anticholinergic and/or non-steroidal antiinflammatory drugs, common therapies for colic pain in humans. Rats implanted with a unilateral ureteral stone were treated for 10 days with: (1) saline; (2) hyoscine-N-butylbromide (15 mg/kg/day i.p.); (3) ketoprofen (15 mg/kg/day); or (4) hyoscine-N-butylbromide + ketoprofen (15 + 15 mg/kg/day). Oblique muscle vocalization thresholds were measured daily for 3 days before and 10 days after operation. Ipsilateral thresholds decreased significantly after stone implantation on: (1) seven days (max. 32%) for saline; (2) one day (max. 20%) for hyoscine-N-butylbromide; (3) one day (max. 18%) for ketoprofen, but did not change significantly for hyoscine-N-butylbromide + ketoprofen. These results indicate a protective effect against muscle hyperalgesia of ureteral origin by spasmolytic and antiinflammatory drugs, maximal when the two treatments are combined.