gateway drug

US /ˈɡeɪtweɪ drʌɡ/
UK /ˈɡeɪtweɪ drʌɡ/
"gateway drug" picture
1.

入门毒品, 引路毒品

a drug whose use is thought to lead to the use of more dangerous drugs (such as heroin or cocaine)

:
Marijuana is often considered a gateway drug by some.
大麻常被一些人认为是入门毒品
The theory of gateway drugs suggests a progression from less harmful to more harmful substances.
入门毒品理论认为,毒品使用会从危害较小的物质发展到危害更大的物质。