Severe acutepoisoning of cypermethrin is rare. We reportedthiscase about a47-year old man who was brought to the Emergency Departmentwith drowsiness and drooling of saliva after intentional self-harm with 2.25gram of cypermethrin.His initial condition was stable. However, nine hours after admission, he developed seizures and reduced conscious level. He was ventilated overnight for airway protection. Management of acute severe poisoning is discussed in this case report.