expression, godan verb (-ru)
poison; drug; slip something into a drink/food
Idiomatic expression meaning to secretly add poison or a drug to someone's drink or food. The literal meaning is 'to serve a dose'.
彼は酒に一服を盛られて、意識を失った。
He had his drink drugged and lost consciousness.
犯人は被害者のコーヒーに一服を盛ったと自供した。
The culprit confessed to having slipped something into the victim's coffee.