Local anaesthetic drugs accidentally injected into arteries may reach the cerebral circulation following a centripetal pathway and then produce central system toxic response s because local anaesthetic can readily cross blood brain barrier. CNS toxicity is usually the first sign of overdose in awake patient. signs of generalized CNS toxicity is dose dependent. low doses produce cns depression and higher doses result in cns excitation and seizure s . symptoms such as dizziness ringing in the ear numbness and tingling of lips or tongue vague sensation of light headedness blurring or doubling of vision along with difficulty in focusing and at times a flushed or chilly sensation slurred speech and fine skeletal muscle twitching in face and digits are usually observed as the initial indication of local anaesthetic toxicity.