Bittersweet Nightshade (Solanum dulcamara) is a perennial vine that must never be consumed due to its significant toxicity. It belongs to the Solanaceae family, which includes edible species like tomatoes and potatoes, as well as highly poisonous ones. All parts of the plant contain toxic compounds, making it unsafe for human and animal consumption. Native to Eurasia, the vine is now widely established across North America and Europe, growing in moist areas like streambanks and woodland edges. Proper identification is important due to its widespread presence.
Identification of Bittersweet Nightshade
Bittersweet Nightshade is a slender, woody, climbing vine that can sprawl along the ground or climb over other vegetation, sometimes reaching up to ten feet. The lower stems are woody, while the upper portions die back annually. Its leaves are distinct, typically dark green, oval, and pointed at the tip.
A primary identifying feature is the leaf shape, which frequently has two small lobes at the base, giving them an arrow-shaped appearance. When crushed, the leaves or stems may release an unpleasant odor. The plant’s small, striking flowers bloom in clusters from late spring into summer.
Each flower is star-shaped, featuring five petals that curve backward, displaying a vibrant purple or blue-violet color. A prominent, cone-shaped column of bright yellow anthers sits at the center, characteristic of the nightshade family. Following the flowers, the vine produces clusters of oval berries.
These berries begin as green, progress to yellow-orange, and ripen into a glossy, bright red. Their attractive appearance, resembling small cherry tomatoes, makes them the most commonly ingested part, particularly by children. Berries and flowers can be present simultaneously, and while toxicity levels change as they ripen, they should never be considered safe at any stage.
Toxic Compounds and Mechanism of Harm
The toxicity of Bittersweet Nightshade stems from steroidal glycoalkaloids, primarily solanine and solasonine. These naturally occurring compounds are biosynthesized by the plant as a defense mechanism against insects and grazing animals. Toxin concentration varies significantly depending on the plant part and maturity, with unripe green berries and young leaves containing the highest levels.
Once ingested, these glycoalkaloids exert harmful effects through a dual mechanism affecting the cellular and nervous systems. The first mechanism involves the disruption of cell membranes, particularly those lining the gastrointestinal tract. The toxins achieve this by binding strongly to 3β-hydroxysterols, such as cholesterol, within the cell membrane structure.
This binding compromises the integrity of the cell membrane, causing cellular damage. This damage leads to the severe gastrointestinal distress commonly experienced after ingestion, including nausea, vomiting, and abdominal pain.
The second mechanism involves neurotoxicity through interference with the nervous system. The glycoalkaloids inhibit the enzyme acetylcholinesterase (AChE), which breaks down the neurotransmitter acetylcholine. Blocking AChE allows acetylcholine to accumulate, leading to overstimulation of nerve impulses. This neurological interference contributes to severe symptoms like confusion, delirium, and loss of coordination.
Symptoms of Poisoning and Emergency Protocol
Symptoms of Bittersweet Nightshade poisoning can manifest relatively quickly after ingestion, often beginning with immediate gastrointestinal distress due to the cellular disruption caused by the glycoalkaloids. Initial signs typically include burning in the mouth and throat, nausea, severe vomiting, and diarrhea. The onset of these symptoms generally serves as a natural defense, limiting the total amount of toxin absorbed.
As the toxins are absorbed into the bloodstream and begin to affect the nervous system, more serious symptoms can develop. These may include headaches, dizziness, and a feeling of weakness or trembling. Neurological effects can escalate to confusion, delirium, vertigo, and loss of coordination. The most severe cases may involve slowed breathing, circulatory issues, and convulsions.
While ripe berries are considered less toxic than the unripe fruit, the possibility of life-threatening symptoms, particularly in small children, means that any ingestion must be treated as a medical emergency.
If Bittersweet Nightshade is ingested, the most important first step is to seek immediate medical help. Do not attempt to induce vomiting or administer any home remedies unless specifically instructed to do so by a medical professional.
Immediately call the national Poison Control Center at 1-800-222-1222 or your local emergency number (such as 911). Be prepared to provide specific information that will guide treatment. This information should include the victim’s age and weight, the part of the plant consumed (e.g., berries, leaves, stem), the estimated amount ingested, and the time the ingestion occurred.