SUMMARYDirect measurement of pelvic and ureteral activity has been used to observe the effect of atropine and buscopan given intravenously. In the majority of cases both had an appreciable effect but individual variation occurs.The technique employed avoids the pitfalls associated with studies on isolated organs and on other species.Observations must be prolonged or erroneous conclusions may be reached.We are grateful to Sir John Bruce, Regius Professor of Surgery, University of Edinburgh for his interest and support. We also wish to thank Dr D. A. Middleton, Boehringer Ingelheim Ltd., for providing funds for part of the equipment used, Dr J. Straton, Consultant Anæsthetist, for many helpful suggestions, and Mr F. Robbie, Superintendent Radiographer, for the reproduction of the tracings