The idea that “poison is a woman’s weapon” is an old, made-up sawhorse. The concept has been invoked in works like Game of Thrones and Sherlock Holmes (not the Cumberbatch version, you didn’t miss anything), and bolstered by popular fiction: the terrifying grandmother from Flowers in the Attic, the adorable little old ladies from Arsenic and Old Lace, very nearly Marie from Breaking Bad, and the evil queen/gnarled old witch from Snow White. It’s a classic conceit: the femme fatale slipping a mickey into a glass of rye, the psychotic nana sprinkling arsenic on her grandchildren’s donuts, the jealous older woman offing her young competitionr, the cherubic nurse who is secretly an angel of death. But as Deborah Blum, author of The Poisoner’s Handbook, points out: 60.5% of poisoners are dudes, leaving only 39.5% of poisonings to the ladies.
Still, compared to other methods for murder, 39.5% of poisoners being female is fairly high – from 2006 to 2010, women represented 21% of arson cases, and only 7.9% of gun murders. There are still many more female arsonists and shooters because those are more popular crimes—in the sample years there were only 49 poisonings total—but it’s still notable. Basically, if someone was poisoned, it’s not particularly likely that the murder was committed by a woman—but if a woman murders someone, it’s somewhat likely it was by poison.