Mosapride citrate (Mosapride) is a new prokinetic agent that enhances the gastrointestinal (GI) motility by stimulation of 5-HT₄ receptors. This agent stimulates acetylcholine release from enteric cholinergic neurons in the GI wall. It was reported in several studies that mosapride selectively enhanced the upper, but not lower, GI motor activity. However, in these studies other 5-HT₄ receptor agonists exerted stimulating effects on the motility of the colon. Moreover, it is well known that the receptors of 5-HT₄ are also located in the colon. The purpose of this study was to estimate the effect of mosapride on the motility of the stomach, ileum and colon in the guinea pig and to investigate whether or not mosapride influenced the colonic motility. Mosapride significantly increased the amplitude of the contraction waves in the guinea pig stomach by electrical stimulation. In addition, it significantly increased the number of peaks, the area under the curve and the propagation velocity of the peristaltic contraction of the guinea pig ileum in a concentration dependent fashion. Mosapride also significantly shortened the transit time of the guinea pig colon. Accordingly, we concluded that mosapride exerted prokinetic effect on the entire GI tract of the guinea pig. Based on the possibility of similar results in humans, we suggest the potential use of mosapride for lower GI motor disorders such as constipation and upper GI motor disorders such as gastroesophageal reflex disease or gastroparesis.