Rapid effects of Kikyo-to on sore throat pain associated with acute upper respiratory tract infection

Abstract Background : Kikyo-to is used empirically for relieving sore throat pain associated with acute upper respiratory tract infection (URTI) in Japan. However, few studies have demonstrated its clinical effect. This study was conducted to investigate the efficacy of Kikyo-to on sore throat pain associated with acute URTI. Methods : Patients with sore throat pain who were diagnosed with URTI in General Medicine Department Office, Tsukuba Medical Center Hospital from January to March 2012 were enrolled. Patients received 2.5 g of Kikyo-to diluted in a cup of hot water. The primary outcome was the change in sore throat score on the visual analog scale (VAS) 10 min after Kikyo-to administration. Secondary outcomes were change in sore throat score on VAS after 30 min and impact of sore throat pain on daily life (none, mild, moderate, and severe) after 10 and 30min. Results : Forty patients were eligible. Mean VAS score was 48.2±18.2 before treatment and reduced significantly to 35.4±18.1 after 10 min and 30.7±19.3 after 30 min (p<0.001 in both periods). The proportion of patients with moderate or more impact of sore throat pain on daily life was 67.5% and was reduced significantly to 37.5% after 10 min and 30% after 30 min (p<0.001 in both periods). The patients reported no side effects. Conclusions : Kikyo-to relieves sore throat pain associated with acute URTI.