If something, especially a drug, has a narcotic effect, it makes the person who uses it feel sleepy.
hormones that have a narcotic effect on the immune system.
对免疫系统有麻醉作用的激素。
narcotics
Narcotics are drugs such as opium or heroin which make you sleepy and stop you from feeling pain. You can also use narcotics to mean any kind of illegal drugs.
He was charged with dealing in narcotics.
他因贩卖毒品而受到起诉。