The effects of two different forms of anticholinergic medication on endoscopic quality and patient discomfort were studied in 235 consecutively observed out-patients. Patients were randomized to receive either scopolamine i.v. and placebo transdermally, saline i.v. and saline transdermally, or placebo i.v. and scopolamine transdermally. No differences could be observed between the groups with respect to gastric motor function or endoscopic quality (as judged by the endoscopist), or discomfort during endoscopy (as judged by the patient). Transdermally applied scopolamin resulted in a significant increase (2p = 0.002) in post-endoscopy discomfort due to dryness of the mouth. The findings speak against the use of i.v. scopolamine (20 mg) or transdermally applied scopolamine (0.5 mg) in endoscopy of the upper gastrointestinal tract.