Nightshade

The nightshades (Solanaceae) are a family of flowering plants. 

Many members of the family contain strong alkaloids, and some are very toxic. Well-known members of this family are chili peppers, petunias, deadly nightshade, mandrakes, potatoes, tomatoes, aubergines (eggplants) and tobacco.

Because it is thought that nightshades can cause or increase swelling and pain, many people do not eat them. The poisons in the plants are defence against animals that might eat them.