Background Gastrointestinal (GI) symptoms during exercise may be caused by GI ischaemia. The authors report their experience with the diagnostic protocol and management of athletes with symptomatic exerciseinduced GI ischaemia. The value of prolonged exercise tonometry in the diagnostic protocol of these patients was evaluated. Methods Patients referred for GI symptoms during physical exercise underwent a standardised diagnostic protocol, including prolonged exercise tonometry. Indicators of GI ischaemia, as measured by tonometry, were related to the presence of symptoms during the exercise test (S+ and S- tests) and exercise intensity. Results 12 athletes were specifi cally referred for GI symptoms during exercise (fi ve males and seven females; median age 29 years (range 15-46 years)). Type of sport was cycling, long-distance running and triathlon.Median duration of symptoms was 32 months (range 7-240 months). Splanchnic artery stenosis was found in one athlete. GI ischaemia was found in six athletes during submaximal exercise. All athletes had gastric and jejunal ischaemia during maximum intensity exercise. No signifi cant difference was found in gastric and jejunal Pco 2 or gradients between S+ and S- tests during any phase of the exercise protocol. In S+ tests, but not in S- tests, a signifi cant correlation between lactate and gastric gradient was found. In S+ tests, the regression coeffi cients of gradients were higher than those in S- tests. Treatment advice aimed at limiting GI ischaemia were successful in reducing complaints in the majority of the athletes. Conclusion GI ischaemia was present in all athletes during maximum intensity exercise and in 50% during submaximal exercise. Athletes with GI symptoms had higher gastric gradients per mmol/l increase in lactate, suggesting an increased susceptibility for the development of ischaemia during exercise. Treatment advice aimed at limiting GI ischaemia helped the majority of the referred athletes to reduce their complaints. Our results suggest an important role for GI ischaemia in the pathophysiology of their complaints.