OBJECTIVES: Gastric motor dysfunction may be responsible, in some patients, for the nausea and emesis that occur after high-dose chemotherapy (HDT) and autologous stem cell transplantation (SCT). Because gastric myoelectrical abnormalities may result in nausea and vomiting in other contexts, we sought to define the prevalence of these abnormalities and their relationship to the development of nausea and vomiting in patients undergoing autologous HDT and SCT, and to determine whether electrogastrography (EGG) could serve to detect gastric motor dysfunction in this population. METHODS: We prospectively studied patients with a variety of malignancies who received standard transplantation doses of chemotherapeutic agents and antiemetics. Gastric emptying scintigraphy was performed before HDT. Gastric myoelectrical activity was assessed before HDT and on days 0, 7, 14, 21, and 28 from SCT using cutaneous EGG electrodes and a portable EGG recorder, and was analyzed by means of a dedicated software program after removal of motion artifact. Symptom assessment was obtained daily from initiation of HDT to 28 days after SCT. RESULTS: A total of 25 patients were studied: 13 women and 12 men, with a median age of 50 yr (range = 32-65 yr). Before HDT, gastric emptying scintigraphy was normal in all patients (median T(1/2) of 50 min [range = 22-75 min]) and only one patient had mild nausea and anorexia. Nausea, emesis, and anorexia occurred in all patients, peaked in severity at day +7 from SCT and, with the exception of anorexia, had returned toward baseline levels by day +28. Fasting dysrhythmias were present in 63% of the studies at baseline. Serial EGG recordings revealed significant slowing of the dominant frequency with a consequent decrease in tachygastria and increase in normogastria and bradygastria as the symptoms peaked in severity with a subsequent return to baseline values at the study's end. The only clinical variable that was predictive of symptom severity was gender. Women had a higher risk of developing anorexia (score > or = 2) at day +14 compared to men (odds ratio = 11.2; 95% CI = 1.7-76.9; p = 0.01). CONCLUSIONS: Baseline abnormalities in gastric myoelectrical activity occur frequently in patients who undergo HDT and autologous SCT despite normal gastric emptying scintigraphy and an absence of symptoms. Although slowing of the dominant frequency was seen as symptoms worsened, we failed to identify any EGG parameter at baseline that could predict the severity of nausea, vomiting or anorexia after transplantation.