。
She choked on cigarette smoke.
Literal
She [topic-は] cigarette [from/by-で] choked.
むせる is the everyday verb for choking on smoke, food, or liquid that's gone the wrong way — distinct from the literary むせぶ ('sob, be choked with emotion') and from 詰まる ('be blocked') for full airway obstruction. The で here marks cause: 'choked because of / from cigarettes.' This causal で is the same particle that gives 風邪で休む ('be off because of a cold') and 雨で中止 ('cancelled because of rain'). A short, vivid sentence — the kind that appears in vocabulary drills precisely because each word carries clean grammatical work.