Aconitum napellus (monk's-hood, aconite, wolfsbane) is a species of flowering plant in the genus Aconitum of the family Ranunculaceae, native and endemic to western and central Europe.

It is an herbaceous perennial plant growing to 1 m (3 ft 3 in) tall, with hairless stems and leaves. The leaves are rounded, 5–10 cm (2.0–3.9 in) diameter, palmately divided into five to seven deeply lobed segments. The flowers are dark purple to bluish-purple, narrow oblong helmet-shaped, 1–2 cm (0.39–0.79 in) tall.