This document summarizes local and general complications that can occur from local anesthesia in dentistry. For local complications, it discusses failure to obtain anesthesia, pain during/after injection, hematoma formation, intravascular injection, blanching, trismus, facial paralysis, lip trauma, prolonged impairment of sensation, broken needles, and infection. For general complications, it mentions fainting, drug interactions, homologous serum jaundice, sensitivity reactions, occupational dermatitis, and cardio-respiratory emergencies. Causes and treatments are provided for many of the complications.