An addictive drug, such as opium, that reduces pain, alters mood and behavior, and usually induces sleep or stupor.Natural and synthetic narcotics are used in medicine to control pain.

• 麻醉剂：一种能使人上瘾的药剂，如鸦片，能够减轻疼痛，改变心情和行为，通常导致沉睡或麻木。