Palmoplantar pustulosis (PPP) is a chronic skin disease characterized by sterile intraepidermal pustules associated with erythematous scaling on the palms and soles. Jumihaidokuto is a traditional herbal medicine composed of ten medical plants and has been given to patients with suppurative skin disease in Japan. This study investigated the effect of jumihaidokuto on the disease activity in PPP patients (n = 10). PPP patients were given jumihaidokuto (EKT-6; 6.0 g per day) for 4 to 8 weeks in addition to their prescribed medications. The results showed that the palmoplantar pustular psoriasis area and severity index (PPPASI) was decreased after the administration of jumihaidokuto (p < 0.05). Therefore, Jumihaidokuto is seemingly effective against PPP.