Rohypnol is a strong sleeping drug, originally a brand name from the Swiss company Roche. Doctors used it to help people sleep or to calm them before an operation. In many countries it is now tightly controlled or banned, because a small dose can knock a person out and leave them with little or no memory of what happened. That is why it became known — ugly as this is to say — as a drug some people secretly put in a drink so that someone cannot defend themselves against rape. In US slang you may hear roofie for a pill of this kind. It is not an ordinary sleeping tablet from a Taiwan pharmacy; treating it as everyday medicine is dangerous and, without a prescription, illegal.

氟硝西泮（原廠商品名 Rohypnol）。台灣一般說 FM2，是強效安眠藥，也因被用於迷姦而惡名昭彰。