Spontaneous tonsillar bleeding (STB) occurs very unusually. In general, it Is assumed that the cause of STB is related to the erosion of superficial vessels on the tonsils, or adjacent vessels such as the facial and internal carotid arteries resulted from bacterial or viral infection of tonsils. Another cause is a benign or malignant tumorous lesion of tonsils. The others are coagulopathy and idiopathic one, etc. According to the current literatures, STB cases mailnly happen in children or young adults, and these examples are increasing in this age groups in recent. Of those cases, life-threatening bleedings are extremely rare events. Early treatments of STB include the compressions with hemostatic agents, electrocauterization, hydration, transfusion and the use of antibiotics. Tonsillectomy is recommended for those who experience recurrent STB. We experienced a case of unilateral tonsillar bleeding without other causes. A 13-year-old male with STB was treated with compression, hydration, and stabilized after transfusion. Full laboratory studies showed no abnormality. 6 days after admission, he was discharged without complication.