Human Effects: Strychnine blocks inhibitory nerve impulses and may produce sensitization to the excit atory impulses in humans. Symptoms of strychnine poisoning begin 15 to 30 minutes after ingestion. There may be an initial violent convulsion, but frequently symptoms begin with restlessness, apprehension, heightened perception (hearing, vision, etc.),abrupt movements, exaggerated reflexes, muscular stiffness of face and legs, and rarely vomiting. Minor stimulation may trigger violent convulsions. Movements may be intermittent at first, but then there is hyperextension, with the body arched convexly, resting on head and heels, the legs extended, arms flexed over chest or rigidly extended, fists clenched, jaw clamped, the face fixed in a grin, and the eyes bulging. Breathing stops and the patient turns blue. The muscles relax completely between convulsions, there is cold sweat, and the pupils may contract. After 10 to 15 minutes, hypersensitivity returns with further convulsions. There may be one to ten such attacks before recovery or death from respiratory arrest (suffocation). The fatal dose is usually in the range of 100-200 mg, but as little as 30 mg in adults and 15 mg in children has proved fatal.