Background: Ethanol ingestion causes a variety of gastrointestinal disturbances including motility disturbances. Slow waves coordinate gastrointestinal motility and abnormal slow-wave activity is thought to contribute to motility disorders. To date however, little is known about the effect of acute ethanol on motility disturbances associated with slow wave activity. Method: 7-10 cm duodenum, jejunum and ileal loops from adult male Wistar rats were isolated and mounted in a 300-ml organ bath superfused with a Tyrode solution (100ml/min). The intestinal loops were connected to an inlet and an outlet and intra-luminally perfused with Tyrode (0.5ml/min). Soot markers were applied onto the serosal surface of the segments. After a 15 min equilibration period, the loops were superfused with 1, 3 and 5% ethanol. Motility recordings were performed with a digital video camera and electrical activities were recorded using a single longitudinal row of 32 extracellular unipolar silver electrodes. Results: In all duodenal, jejunal and ileal segments (n=7), ethanol inhibits motility fully at 3% and 5%. The slow wave activity was also were altered at all the concentration in terms of velocity, frequency and amplitude ethanol. All effects were reversible upon superfusing with normal Tyrode. Summary: Acute application of ethanol caused widespread but reversible inhibition of slow wave propagation with concurrent inhibition of small intestinal motility.