BACKGROUND Colonic motility and spasm during colonoscopy may affect duration and quality of the examination as well as patient comfort during and after the procedure. Previous studies assessing the utility of antispasmodic agents in colonoscopy demonstrated conflicting results. The aim of this study was to determine the effect of sublingual hyoscyamine spray (IB-Stat, Inkine Pharmaceutical) on the performance of colonoscopy. METHODS One hundred patients undergoing elective colonoscopy were randomized in a double-blind study to receive .25 mg sublingual hyoscyamine spray (n = 50: 25 men and 25 women, mean age 60) or placebo spray (n = 50: 23 men and 27 women, mean age 56) 15 to 30 minutes before the procedure. Parameters measured included time required to reach the cecum, total procedure time, endoscopist perception of colonic motility and difficulty of the procedure, and patient assessment of discomfort after the procedure. The latter parameters were measured using a 100-mm visual analog scale. A single endoscopist performed all of the procedures. RESULTS After adjustment for age, procedural difficulty scores and colonic motility scores were significantly lower in the hyoscyamine group compared with placebo (differences of 5.589 mm [P = .047] and 5.685 mm [P = .040], respectively). Mean time to cecal intubation and percentage of patients with discomfort were slightly lower in the hyoscyamine group (5.68 minutes/48%) compared with placebo (5.92 minutes/57.1%), although the differences were not statistically significant (P = .57 and P = .36, respectively). CONCLUSIONS Procedural difficulty and colonic motility scores were significantly lower in subjects who received sublingual hyoscyamine before colonoscopy.