A Short History of the Ostensibly Deadly Nightshade

Nightshade — the name alone sounds mysterious and ominous. Vegetables and plants that fall within this family have been labeled with terms like poisonous and deadly. Some get a bad rap for contributing to chronic health conditions. Yet we eat many of these vegetables on a regular basis. So, what’s really the deal with the ostensibly deadly nightshade?

Nightshades are a family of plants, including vegetables, herbs, weeds, and shrubs, technically referred to as Solanaceae. There are thousands of plant species that fall into this family, and all share some common characteristics, like how the seed is arranged within the fruit and the shape of the flower.

Most nightshade plant species are inedible, although the family includes ones that we eat every day, including many varieties of peppers (both hot and bell peppers) and potatoes, tomatoes, eggplant, and even tobacco. While at first glance these vegetables don’t seem to be related by look or taste, the one thing they share in common is that each plant sprouts the same type of flower.

Nightshades derive their deadly reputation from the presence, in varying degrees, of different alkaloids and the effect they can have on the human body, with the deadliest of nightshades being plants we don’t generally consider edibles — particularly the mandrake and belladonna — rather than vegetables.

The history of the mysterious and mystical nightshade goes back hundreds of years, with stories of plants in this family being used as potent narcotic medicines and sleeping pills, in witchcraft, and even as murderous poisons. The mandrake is mentioned as far back as the Old Testament, and has a presence in popular literature from Shakespeare to Chaucer, even Harry Potter. And on a historical note, the Romans were said to use this plant to poison their enemies during war.

Nightshades have also been used in cosmetics. Specifically belladonna, which was used as a narcotic but also by women to dilate their pupils to appear more attractive.

Because of their relationship to the far more deadly belladonna, mandrake, and other toxic nightshades, the edible nightshade vegetables that we know and enjoy today were largely avoided until the 1800s. A simple case of guilt by association.

While not all members of the nightshade family are deadly, some people experience sensitivities when eating these vegetables because of the presence of different alkaloids like solanine, nicotine, and capsaicin, so it’s best if you have those sensitivities to avoid nightshade edibles.

But, in the end, it’s all a matter of degree — the edible nightshades we know and love have far lower levels of alkaloids in their chemical makeup than do the more toxic varieties. And this is the way so much of the natural world works; toxic substances are all throughout living things, and can even be healthy in small amounts (think: vitamin A, or really any major vitamin). The dose makes the poison.

• Wicked Plants: The Weed That Killed Lincoln’s Mother and Other Botanical Atrocities by Amy Stewart