Poisonberry Plant (Solanum nigrum): Toxicity, Traditional Uses, and Safety

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The poisonberry plant (Solanum nigrum), known to botanists as black nightshade, is a common weed with a confusing reputation. Parts of it are eaten as a cooked vegetable in some countries, other parts can make you sick, and its nickname gets it tangled up with one of the most poisonous plants in Europe. If you have found a sprawling, knee-high weed with small white star-shaped flowers and clusters of shiny black berries, this is most likely what you are looking at.

The most important thing to know up front: the poisonberry plant is not the same plant as deadly nightshade. They are different species, and mixing them up can be dangerous [NC State Extension].

Poisonberry plant vs. deadly nightshade

Common names cause real harm here. “Deadly nightshade” is the name for Atropa belladonna — a separate plant in the nightshade family (Solanaceae) whose berries are genuinely lethal, especially to a child. The poisonberry plant, Solanum nigrum, belongs to a different genus and is far less dangerous, though it is still not something to eat casually [Kew POWO] [NC State Extension].

The two are easy to tell apart once you know what to look for. Black nightshade carries small berries in little hanging clusters, and its flowers have five white petals around a yellow center. Deadly nightshade bears its berries singly, and its flowers are larger, bell-shaped, and dull purple. If a plant has solitary purple bell-flowers and single black berries, treat it as deadly nightshade and leave the fruit alone.

Feature	Poisonberry / black nightshade (Solanum nigrum)	Deadly nightshade (Atropa belladonna)
Flowers	Small, white, star-shaped, five petals	Larger, bell-shaped, dull purple
Berries	Small, growing in clusters	Larger, growing singly
Main toxins	Solanine and related glycoalkaloids	Tropane alkaloids (atropine, scopolamine)
Danger level	Toxic, mainly the green parts; rarely fatal	Highly toxic; a small amount can kill
Eaten as food?	Ripe berries and cooked leaves, in some regions	Never

Toxin profiles per [ScienceDirect / Encyclopedia of Toxicology, 2024].

What the poisonberry plant actually is

Solanum nigrum is an annual, sometimes short-lived perennial herb that grows up to about a meter tall, with dark green oval leaves and hairy, green-to-purplish stems [NC State Extension]. Despite the old claim that it came from the Americas, the plant is native to Eurasia and was carried around the world later. It now grows as a weed in fields, gardens, roadsides, and waste ground [Kew POWO] [J. Ethnopharmacol, 2025].

It goes by many names — black nightshade, common nightshade, garden nightshade, blackberry nightshade, and, in parts of South Asia, makoi or kakamachi. The genus name Solanum comes from a Latin word meaning “soothing,” a nod to its long history in folk medicine [NC State Extension].

Quick reference:

• Scientific name: Solanum nigrum L.
• Family: Solanaceae — the same family as tomato, potato, eggplant, and pepper
• Other names: black, common, garden, and blackberry nightshade; makoi; poisonberry
• Where it grows: fields, gardens, walls, and disturbed ground across temperate and warm regions
• Most toxic parts: unripe green berries, plus the leaves and stems

Is the poisonberry plant poisonous?

Yes — but the picture is more nuanced than the name suggests. The plant’s toxicity comes mainly from solanine, a glycoalkaloid that also builds up in green or sprouting potatoes [Encyclopedia of Toxicology, 2024]. Solanine was first isolated from black nightshade berries back in 1820, which is how it got its name [ScienceDirect].

The toxin concentrates in the green, unripe berries and in the leaves and stems. Ripe black berries of edible strains contain far less solanine, and in parts of Africa, India, and elsewhere the fully ripe fruit and thoroughly cooked leaves are eaten as food [J. Ethnopharmacol, 2025] [Children’s Health Queensland, 2024]. Even so, telling an edible strain and a fully ripe berry apart is harder than it sounds, the toxin content swings from plant to plant, and the green parts stay risky. For most readers the safe rule is plain: do not eat any part of a wild nightshade. If you want the nutrients found in dark leafy greens, everyday vegetables are a far safer source.

Symptoms of nightshade (solanine) poisoning

Solanine is absorbed poorly from the gut, so small exposures often pass with nothing worse than stomach upset [ScienceDirect]. Its effects fall mainly on the digestive tract and the nervous system. Larger amounts can cause:

• nausea, vomiting, stomach cramps, and diarrhea
• a burning feeling in the throat
• headache, dizziness, and a fast pulse
• in severe poisoning, confusion, hallucinations, or muscle weakness

Symptoms can be delayed. In one documented outbreak, frozen green beans accidentally contaminated with unripe black nightshade berries caused poisoning that began seven to ten hours after the meal, and two children needed a day of hospital observation [Encyclopedia of Toxicology, 2024].

What to do if you think someone has been poisoned

If a person — or a pet — has eaten any part of a nightshade and seems unwell, treat it as a possible poisoning. In the United States, call Poison Control at 1-800-222-1222, which is free and answered around the clock; outside the US, contact your local poison center or emergency number. Do not wait for severe symptoms to appear, and do not try to make the person vomit unless a professional tells you to. The plant is listed as poisonous to children, dogs, cats, and horses [NC State Extension].

Traditional uses and the state of the evidence

Black nightshade has a long record in traditional medicine. In Ayurveda, Unani, and traditional Chinese medicine, the leaves and berries have been used for swelling, liver complaints, inflammation, and skin conditions such as ringworm and itching, more often applied to the skin than swallowed [PMC review, 2022]. Laboratory chemists have catalogued well over a hundred compounds in the plant, including steroidal alkaloids, flavonoids, and polysaccharides [PMC review, 2022].

Here is the honest part. Most of the reported effects — antioxidant, anti-inflammatory, antimicrobial, liver-protective, and anti-tumor activity — come from test-tube studies and animal experiments, not from well-run trials in people. A 2025 review of the published literature found a wide range of activity in the lab but concluded that solid clinical evidence in humans is still limited and that better-designed trials are needed [J. Ethnopharmacol, 2025]. Laboratory promise is not the same as a proven treatment. None of this supports using the plant to treat a disease at home, and the single most studied compound in it — solanine — is a toxin, not a remedy.

Safety, side effects, and who should avoid it

Because the plant is toxic and barely studied in people, caution is the only sensible default.

Who should avoid it entirely:

• Children and pets. They are most at risk from the berries, and most accidental poisonings involve a child eating the fruit [NC State Extension].
• Anyone pregnant or breastfeeding. There is no safety data to support use, and the plant contains active alkaloids.
• People taking prescription medicines. Black nightshade has not been tested for drug interactions, and self-dosing an alkaloid-containing plant alongside medication is a needless risk.

The side effects of eating the plant are the poisoning symptoms above: mild stomach upset at low doses, and potentially serious effects at higher ones. There is no established safe dose for medicinal use.

A realistic expectation: there is currently no good human evidence that eating, drinking, or applying poisonberry treats any medical condition. If you have a skin problem, an infection, or a long-term illness, this plant is not a substitute for care that actually works.

When to talk to a doctor or seek urgent care

See a healthcare professional promptly if you or someone else may have swallowed any part of a nightshade plant, especially a child. Seek urgent or emergency care for repeated vomiting, severe stomach pain, a racing or irregular heartbeat, confusion, hallucinations, trouble breathing, drowsiness that is hard to rouse from, or any collapse. Those are red flags, not symptoms to ride out at home. When you are not sure whether an exposure is serious, a poison center can tell you what to watch for and whether you need to be seen.

Health Disclaimer This article is for general education and information only. It is not medical advice and is not a substitute for diagnosis or treatment from a qualified health professional. Solanum nigrum is a toxic plant; do not eat, brew, or apply any part of it to treat a health condition. If you are pregnant, breastfeeding, taking medication, or managing a medical condition, talk to your doctor before using any herbal or natural product. If you suspect poisoning, contact Poison Control (1-800-222-1222 in the US) or your local emergency number right away.

Frequently asked questions

References

1. Plants of the World Online (POWO). “Solanum nigrum L.” Royal Botanic Gardens, Kew.  → View source
2. North Carolina Extension Gardener Plant Toolbox. “Poisonberry — Solanum nigrum.” NC State University.  → View source
3. Children’s Health Queensland Poisons Information Centre. “Blackberry nightshade (Solanum nigrum).” 2024.  → View source
4. San Andrés Larrea, M. I., et al. “Solanum nigrum.” Encyclopedia of Toxicology (Fourth Edition), 2024 (via ScienceDirect Topics).  → View source
5. “Solanine.” ScienceDirect Topics (Pharmacology, Toxicology and Pharmaceutical Science).  → View source
6. “Progress in Solanum nigrum L. research: traditional uses, phytochemistry, pharmacological activities, quality control, and clinical applications.” Journal of Ethnopharmacology, 2025.  → View source
7. “Solanum nigrum Linn.: An Insight into Current Research on Traditional Uses, Phytochemistry, and Pharmacology.” 2022 review (PMC).  → View source