Sudden sore throat may be due to acute pharyngitis, acute tonsillitis, peritonsillar abscess. Generally due to viral, bacterial and environmental factors such as mucous membranes, pharyngeal submucosal tissue acute inflammation. 1. Acute pharyngitis: viral infections such as adenovirus, coxsackie virus and parainfluenza virus are common. Rhinovirus and influenza virus are the next most common. Infection through droplets, close contact. Pharyngeal mucosal congestion. May also be bacterial infection-. Staphylococcus, Streptococcus, and Streptococcus pneumoniae are common. Group A Streptococcus B infection is the most serious and can lead to purulent lesions in distant organs. 2. Acute tonsillitis: acute non-specific inflammation of the tonsils, often accompanied by varying degrees of inflammation of the pharyngeal mucosa and lymphoid tissue. Type B hemolytic streptococcus is the common causative agent. It can be transmitted directly through droplets. 3. Peritonsillar abscess: purulent inflammation that occurs in the peritonsillar space, often secondary to acute tonsillitis. Due to the tonsil crypt, bacterial infection makes the mouth of the crypt appear blocked, bacteria or inflammatory products destroy the epithelial tissue, to the deep invasion, penetrate the tonsil peritonsillar membrane, into the tonsil peritonsillar gap. Sudden throat pain, do not self-medication, need to consult a doctor as soon as possible to clarify the diagnosis, to avoid causing serious complications.