ABSTRACTAimThe aim of this study was to identify specific indications for treatment with either yokukansankachimpihange or chotosan, Kampo agents commonly used to treat headache refractory to conventional treatments.MethodsOn multidimensional contingency table analysis using the Kampo database, specific symptoms associated with positive outcome for each agent were identified according to Akaike information criterion, and logit regression was used to predict outcome for both agents in individual patients. This predictive model was validated in another 157 patients (M/F, 12/145; age, 20–84 years). The Kampo treatment with the higher probability of positive outcome in each patient was then used for that patient for 1 month.ResultsSpecific symptoms identified as indications for yokukansankachimpihange were stiffness in the back (partial regression coefficient, 2.25), painful sensation in the eyes (3.28), and irritability (0.25). Those for chotosan were morning headache (partial regression coefficient 3.68), vasodilatation of sublingual veins (1.62), and stiff shoulder (1.28). Yokukansankachimpihange may mainly relieve triggering factors of headache. In the validation study, the model predicted greater efficacy for yokukansankachimpihange in 79 patients (M/F, 4/75; age, 20–84 years) and for chotosan in 78 patients (M/F, 8/70; age, 22–78 years). After treatment for 1 month, the predictive accuracy was 76%.ConclusionsSix symptoms serving as practical indications for selection of either yokukansankachimpihange or chotosan to treat patients with headache, were identified.