It is a delicate perennial often cultivated as an annual. It grows 40 to 150 cm (16 to 57 in) tall, with large coarsely lobed leaves that are 10 to 20 cm (4–8 in) long and 5 to 10 cm (2–4 in) broad. (Semi-)wild types can grow much larger, to 225 cm (7 ft) with large leaves over 30 cm (12 in) long and 15 cm (6 in) broad. The stem is often spiny. The flowers are white to purple, with a five-lobed corolla and yellow stamens. The fruit is fleshy, has a meaty texture, and is less than 3 centimetres (1.2 in) in diameter on wild plants, but much larger in cultivated forms.
The most widely cultivated varieties (cultivars) in Europe and North America today are elongated ovoid, 12–25 cm wide (4½ to 9 in) and 6–9 cm broad (2 to 4 in) in a dark purple skin.