Background and Objective : Peritonsillar abscess occurs when the bacterial infection of the palatine tonsil spreads to the potential peritonsillar space deep behind the tonsil. We observed and treated a case of peritonsillar abscess patient from a child acute tonsillitis. We present this case because there were no former reports of peritonsillar abscess treated by herbal medicine. Methods : We used herbal medication for 24 days. We diagnosed the patient through abdominal examination and have decided the treatment principle accordingly. We used the visual analogue scale(VAS). Results : After the treatment the grade of VAS was decreased and clinical symptoms were improved. Conclusions : Gejigajagyak-Tang in considerably effective on the treatment of pus of peritonsillar abscess.