['Intraluminally administered peppermint oil (PO) is reportedly a safe and useful antispasmodic for gastroscopy, colonoscopy and double-contrast barium enema. The aim of this study was to examine the efficacy of oral PO for double-contrast barium meal examination (DCBM) without other antispasmodics.', 'Two hundred and five randomly chosen subjects (PO group) and 215 sex- and age-matched controls were enrolled. All participants underwent DCBM. The PO group was orally administered PO and a barium suspension mixture at the start of DCBM. Radiographs were blindly evaluated for spasm and overlapping with barium-filled duodenal loops (scored 0-3, indicating none to severe). The quality of barium coating of the mucosa and overall diagnostic quality (scored 0-3, indicating not acceptable to excellent) were also evaluated.', 'There was no significant difference in subject acceptance between PO group and controls, and no adverse effects in either group. Scores for spasm at the esophagus, lower stomach and duodenal bulb were significantly lower in the PO than in the control group (P < 0.001). Scores for overlapping at the lower stomach and duodenal bulb were significantly lower in the PO than in the control group (P < 0.05, P < 0.01, respectively). Scores for overall diagnostic quality at the esophagus, lower stomach and duodenal bulb were significantly higher in the PO than in the control group (P < 0.001). Oral PO reduces spasm of the esophagus, lower stomach and duodenal bulb, inhibits barium flow to the distal duodenum, and improves diagnostic quality without other antispasmodics.'] Is oral peppermint oil a useful antispasmodic for double-contrast barium meal examination?