The analgesic and spasmolytic effects of dipyrone (Novalgin) (2500 mg/100 kg bodyweight) hyoscine-N-butylbromide (Buscopan) (20 mg/100 kg bodyweight) and a combination of both drugs were evaluated in a balloon-induced model of colic, using five ponies with caecal fistulae. The drugs were given intravenously and 0.9 per cent sodium chloride solution (5 ml/100 kg bodyweight) was used as a control. The physiological saline solution and dipyrone had no effect on caecal contractions. After the injection of hyoscine-N-butylbromide and the drug combination caecal contractions ceased within 30 seconds and for 20 and 24 minutes, respectively (P less than 0.05). The results on pain relief were not statistically significant for any of the drugs. Dipyrone had a good analgesic effect in only two of the ponies, starting after eight to 10 minutes and lasting for 50 minutes. The drug combination relieved pain within 30 seconds after injection and the relief lasted for 50 minutes in three of the ponies and for 20 minutes in the other two. Hyoscine-N-butylbromide alone produced an analgesic effect within 30 seconds after injection which lasted for 20 minutes.