。
She killed herself by taking poison.
Literal
She [topic-は] poison [object-を] drink-and committed-suicide.
毒を飲んで is a stock collocation — 飲む ('drink') applies broadly to liquid intake, including ingesting medicine or, here, poison. 自殺する ('commit suicide') is a 漢語 + する verb. The te-form 飲んで links the means ('drinking poison') to the result ('committed suicide').