We combined edrophonium provocative testing with the technique of radionuclide oesophageal transit (RET) in 30 consecutive patients with non-cardiac chest pain (NCCP) and 12 controls. The oesophageal transit time of aqueous technetium-99m sulfur colloid was determined before and after intravenous infusion of 80 gg/kg edrophonium chloride (ED). Patient symptoms during provocative RET (P-RET) were recorded. Thirteen (43%) of the patients had abnormal study results, whereas all control subjects had normal results. Three groups considered abnormal were observed' (a) in two patients (6%), the pain was reproduced and transit pre-and post-ED administration was prolonged (> 15 s); (b) in six patients (20%), the pain was reproduced, but transit was normal pre-and post-ED; (c) in five patients (17%), transit pre-and post-ED was prolonged, but no pain was reproduced. In five patients (17%), ED prolonged the transit time >15 s without pain, but the baseline transit was normal. Transit time was measurable in 23 patients. Mean pre-ED transit time was 10.2_+7.4 s (mean__SD) and post-ED, 12.4_+8.0 s (P= 0.3). We conclude that ED has no significant effect on transit time, and the pain induced by ED rarely correlates with an abnormal transit; P-RET provides additional information to baseline RET, increasing sensitivity, and may be a useful screening method in the evaluation of patients with NCCP.