Patients that were treated with rhubarb-containing Kampo extracts (manufactured prescriptions) or Kampo formulae (decoctions) for more than 12 months were enrolled in this study from Japan. Patients were divided into two groups according to rhubarb dose. These groups were compared for age, sex, shape of stool, abdominal symptoms, existence of haemorrhoids, Kampo diagnosis of abdomen, past stimulant laxative use, duration of stimulant laxative use before the first administration of rhubarb, duration of rhubarb use in the hospital, and initial existence of stimulant pain caused by taking stimulant laxatives for the first time. No significant difference was shown between the two groups in terms of age, duration of stimulant laxative use before the first prescription of rhubarb, shape of stool, abdominal symptoms, existence of haemorrhoids, or duration of rhubarb use. However, most patients in the regular-dose group had initial stimulant pain of the abdomen upon taking stimulant laxatives for the first time, but most patients in the excess-dose group did not. All patients except one in the regular dose group had the sign ‘umbilical region tenderness on pressure’ but half of the excess-dose group did not. The authors believe that the absence of ‘initial stimulant pain’ and the absence of ‘umbilical region tenderness on pressure’ may predict increasing or excess use of rhubarb, and long-term use of rhubarb should be discouraged more strongly in the patients without these signs.