Why is the Solanaceae family sometimes called the poisonous family?

The Solanaceae family has about ninety genera and more than 2000 species. There are food, medicinal and ornamental plants here. Most are herbs.
Among the trees, the tomato tree cyfomandra, originally from South America, is especially interesting. Fruits are small in size, in different shades of red, edible, suitable for preparations in the form of compotes, as well as heat treatment (frying).
Ornamental plants include petunia, scented tobacco, dope, nikandra physalis. Nikandra is also used in medicine, like mandrake, which has a strong hallucinogenic effect.
Poisonous substances are also found in henbane, belladonna, dope, as well as in other representatives of the species. It is known that even young potatoes can contain toxic substances.