The tonic component of the electrogastrogram (EGG) has been shown to differentiate duodenal ulcer patients from healthy individuals (15). It has therefore been of considerable interest to investigate the possibility that individuals can learn to modify electrogastric activity. Using a discriminative conditioning paradigm with analogue feedback (Experiment I), subjects were generally unsuccessful at controlling tonic EGG activity. However, when the conditioning paradigm was altered (Experiment II) it was clear that subjects were able to modify specific electrogastric changes. In addition to EGG, heart rate, respiration, abdominal muscle activity, and digital blood flow were measured in order to assess the physiological concomitants of learned control of gastrointestinal activity. Subjects who evidenced discriminative control also showed the least amount of abdominal muscle activity and reported being the most relaxed. The results of these studies suggest that exploration of the physiological processes underlying the electrical activity of the gastrointestinal system and the ability of individuals to modify this activity may lead to significant clinical and theoretical advances.