Patients after bone marrow or stem cell transplant often develop gastrointestinal symptoms. The aim of this study was to investigate possible impairment of gastric myoelectrical activity in these patients. The study was performed in 15 patients who had had bone marrow or stem cell transplant and 13 healthy subjects. Gastric myoelectrical activity was assessed using electrogastrography. The electrogastrogram (EGG) was made for 30 min in the fasting state and 60 min after a test meal (475 kcal; turkey sandwich). Overall and minute-by-minute spectral analyses were performed to derive various parameters of the EGG. Compared with the healthy controls, the patients showed a significantly higher percentage of arrhythmia (no obvious rhythmicity observed in the EGG) in both fasting (17.6 +/- 3.8% vs 7.1 +/- 2.17%, P < 0.02) and fed (11.4 +/- 2.65% vs 4.19 +/- 1.04%, P < 0.02) state. The patients showed a significantly higher instability coefficient of the dominant frequency in the fasting state than in the controls (0.51 +/- 0.06 vs 0.29 +/- 0.18, P < 0.008). The total average symptom score was 3.93 +/- 0.84 in the patients and 0 in the controls, and a relatively weak but significant correlation was found between the symptom scores and the percentage of arrhythmia in the patients in fed state (r = 0.69, P < 0.02). It was concluded that patients with bone marrow or stem cell transplant have excessive arrhythmia that is correlated with their dyspeptic symptoms.