Bryonia is a small genus of climbing vines in the cucumber family (Cucurbitaceae) that spans from the Canary Islands to Central Asia, with around ten recognized species that have drawn attention from botanists, toxicologists, weed managers, and pharmacologists alike. These fast-growing perennial vines produce large tuberous roots, coiling tendrils, and clusters of berries that range from red to black depending on the species. Despite their superficial resemblance to ornamental garden climbers, Bryonia plants are genuinely dangerous: the roots and berries contain potent toxic compounds called cucurbitacins, and as few as 40 berries can be fatal to a person or livestock animal.1Utah State University Extension. White Bryony (Bryonia alba) What makes the genus fascinating is the tension between its toxicity and its long history in folk medicine, its ecological role as both a native wildflower and an aggressive invasive weed, and its ongoing relevance in laboratory research.
A Ten-Million-Year-Old Lineage
Bryonia belongs to the gourd family, making it a relative of cucumbers, melons, and squashes. Its closest living relative is Ecballium elaterium, the aptly named squirting cucumber. Molecular clock analyses estimate that the deepest split within the genus, between a species on the Canary Islands and the ancestor of all remaining Bryonia, occurred roughly ten million years ago.2American Journal of Botany (via PubMed Central). Hybridization, polyploidy, and evolutionary transitions between monoecy and dioecy in Bryonia (Cucurbitaceae) That is a surprisingly ancient origin for a genus of only about ten species, and it tells us that Bryonia’s ancestors have been winding their way across Eurasian landscapes since well before the Mediterranean basin took its modern shape.
The genus comprises seven dioecious species (with separate male and female plants) and three monoecious species (where each plant carries both male and female flowers). Phylogenetic studies using both chloroplast and nuclear DNA show conflicting signals, which is a hallmark of past hybridization events. One particularly interesting result is that B. cretica, a hexaploid (six sets of chromosomes) dioecious species, appears to have arisen from hybridization among diploid ancestors such as B. dioica, B. syriaca, and B. multiflora. A tetraploid population endemic to Corsica and Sardinia likely arose from B. dioica through simple chromosome doubling rather than hybridization.3American Journal of Botany (via PubMed Central). Hybridization, polyploidy, and evolutionary transitions between monoecy and dioecy in Bryonia (Cucurbitaceae) The sexual system has shifted at least twice within the genus, making Bryonia a natural laboratory for studying how plants evolve separate sexes.
How Bryonia Climbs
Like many cucurbits, Bryonia uses tendrils to haul itself upward through vegetation, across fences, and over anything else in its path. What sets Bryonia tendrils apart is their extraordinary sensitivity to touch, which has made them one of the most studied examples of plant mechanosensation in the scientific literature. The key structures are microscopic dome-shaped bumps on the tendril surface called “tactile bleps.” These tiny protrusions, only about four to five micrometers across at their base, are distributed evenly on both the upper and lower surfaces of the tendril.4Bioinspiration & Biomimetics. Taking inspiration from climbing plants: methodologies and benchmarks—a review
Tactile bleps are made from a mix of cellulose, callose, cytoplasm, and cell wall material, and they are more sensitive to shearing forces (sideways rubbing) than to direct pressure.5Bioinspiration & Biomimetics. Taking inspiration from climbing plants: methodologies and benchmarks—a review When a tendril brushes against a branch or wire, the shear triggers a rapid coiling response. Within minutes the tendril begins to wrap around the support, and over the following hours it forms a characteristic helical spring between the plant stem and the attachment point. That spring shape is not just decorative; it functions as a shock absorber, allowing the vine to flex in wind without either snapping or pulling free from its support.
Robotics engineers and materials scientists have studied Bryonia tendrils as models for soft gripping mechanisms. The ability of a slender, flexible structure to detect contact, wrap around an irregularly shaped object, and form a self-tensioning spring has direct parallels in the design of robotic manipulators and adaptive climbing robots.
The Cucurbitacin Problem
Bryonia’s toxicity comes primarily from cucurbitacins, a class of bitter-tasting triterpene compounds that the plant produces in abundance, especially in its roots and berries. These chemicals are the same family of compounds responsible for the extreme bitterness that occasionally shows up in backyard-grown cucumbers and squash, though Bryonia produces them at concentrations far beyond what any edible cucurbit reaches. The roots of B. cretica alone have yielded at least 18 distinct cucurbitane-type triterpenes and glycosides, including two compounds unique to the species called bryoniaosides A and B.6Chemical and Pharmaceutical Bulletin. Cucurbitane-Type Triterpenes with Anti-proliferative Effects on U937 Cells from an Egyptian Natural Medicine, Bryonia cretica: Structures of New Triterpene Glycosides, Bryoniaosides A and B
What makes cucurbitacins dangerous is the way they interfere with the internal scaffolding of cells. Laboratory studies have shown that cucurbitacins B, E, and I all disrupt the mitotic spindle, the structure that pulls chromosomes apart during cell division, causing cells to stall in the G2/M phase and stop dividing. They also depolymerize and aggregate actin filaments, the protein fibers that give cells their shape and enable them to move.7PeerJ. Cucurbitacins: elucidation of their interactions with the cytoskeleton In plain terms, cucurbitacins attack two of the cell’s most fundamental structural systems simultaneously. This dual disruption explains both the poisoning symptoms in animals and the interest pharmacologists have taken in these compounds as potential anticancer agents.
In a living person or animal who eats Bryonia berries or roots, the result is violent gastrointestinal distress: cramping, vomiting, and bloody diarrhea, followed in severe cases by organ damage and death. As few as 40 berries can be lethal.8Utah State University Extension. White Bryony (Bryonia alba) Children and animals are at particular risk because the berries can be visually appealing, clustered in bright red (B. dioica) or black (B. alba) bunches at a height reachable by small hands or browsing livestock.
White Bryony as an Invasive Weed
Of the ten or so Bryonia species, B. alba (white bryony) has caused the most ecological headaches outside its native range. In parts of the western United States, particularly in Idaho, Utah, and neighboring states, white bryony has become a serious invasive species. The vine is an aggressive perennial that regrows each spring from a massive tuberous root that can weigh several kilograms and survive deep underground through harsh winters. Slender tendrils allow it to climb and smother trees, shrubs, and fences, and when it runs out of things to climb, it spreads across the ground in dense mats.9Utah State University Extension. White Bryony (Bryonia alba)
The ecological damage is concentrated in riparian zones, the moist corridors along rivers and streams where native vegetation is already under pressure from development and agriculture. White bryony overwhelms and smothers native plants in these areas, reducing biodiversity.10Utah State University Extension. White Bryony (Bryonia alba) It also invades agricultural lands and residential landscapes, where its vigorous growth can cover fences, outbuildings, and garden plantings in a single season. Control is difficult because even small fragments of the root left in the soil can regenerate. Mechanical removal requires excavating the entire root, which may be buried more than a foot deep, and herbicide treatments often require multiple applications over several years.
In Europe, where both B. alba and B. dioica are native, these species are part of the natural hedgerow flora and rarely cause the kind of damage seen when they establish in ecosystems without the full complement of native herbivores, pathogens, and competitors that keep them in check at home. The contrast between their behavior in Europe and in the American West is a textbook example of how plants released from their natural ecological controls can become destructive invaders.
A Long and Troubled History in Folk Medicine
Bryonia’s medicinal use stretches back to antiquity. In Europe, white bryony had a reputation as an effective laxative and purgative, exploiting the very gastrointestinal irritation that makes the plant toxic at higher doses.11PubMed Central. From medicinal plant to noxious weed: Bryonia alba L. (Cucurbitaceae) in northern and eastern Europe It was also used externally as a poultice for joint pain and bruising, and the large tuberous root was sometimes carved into crude human figures and sold as a cheaper alternative to mandrake root, another medicinal plant with a reputation for magical properties. The resemblance was close enough that some historical sources refer to Bryonia roots as “false mandrake.”
The line between medicine and poison was razor-thin. Herbalists who prescribed Bryonia preparations understood that the dose had to be carefully controlled, and poisoning incidents from misuse were common enough to earn the plant a fearsome reputation. By the nineteenth century, mainstream European medicine had largely moved away from Bryonia, though homeopathic practitioners adopted it and still use highly diluted preparations today.
Bryonia in Laboratory Cancer Research
The same cytoskeletal disruption that makes cucurbitacins toxic to healthy tissue has made Bryonia extracts a subject of ongoing laboratory cancer research. The logic is straightforward: if you can target the compounds specifically at cancer cells, their ability to halt cell division and trigger programmed cell death could be therapeutically useful. Multiple Bryonia species have shown activity in cell culture experiments, though it is important to stress that cell culture results are a very early step in the drug development process and do not translate directly to treatments.
Root extracts of B. aspera, for instance, reduced the viability of cervical cancer (HeLa) and head-and-neck cancer (HN-5) cell lines in a dose- and time-dependent manner, with programmed cell death confirmed by flow cytometry analysis.12PubMed Central. Cytotoxic and apoptogenic effects of Bryonia aspera root extract against Hela and HN-5 cancer cell lines The same species showed cytotoxic effects against pre-B acute lymphoblastic leukemia cell lines (NALM-6 and REH), with a somewhat lower toxicity against normal kidney cells, suggesting at least some degree of selectivity.13PubMed Central. Cytotoxic and Apoptogenic Activity of Bryonia aspera Extract on Pre-B Acute Lymphoblastic Leukemia Cell Lines
A more recent study on B. laciniosa seed extract examined its effects on colorectal and liver cancer cell models and used computational modeling to investigate which molecular pathways were being disrupted. The extract appeared to reduce AKT-1 protein levels and increase p53 expression, two changes that together shift the balance toward cell death and away from unchecked growth.14PubMed. In vitro and in silico evaluation of the anticancer potential of ethanolic seed extract of Bryonia laciniosa against colorectal and hepatocellular cancer AKT-1 is a protein that promotes cell survival, while p53 is the most well-known tumor suppressor. Knocking down one while boosting the other is a strategy that mainstream cancer drug development has pursued with synthetic compounds for decades, so finding the same pattern in a plant extract is scientifically interesting even if clinical application remains far off.
The cucurbitane-type triterpenes from B. cretica roots, including the novel compounds bryoniaosides A and B, were originally isolated through bioassay-guided fractionation aimed at identifying which specific molecules had anti-proliferative effects.15Chemical and Pharmaceutical Bulletin. Cucurbitane-Type Triterpenes with Anti-proliferative Effects on U937 Cells from an Egyptian Natural Medicine, Bryonia cretica: Structures of New Triterpene Glycosides, Bryoniaosides A and B The sheer number of distinct triterpenes found in a single species, at least 18, gives researchers a library of related but structurally distinct molecules to compare, which can help clarify exactly which chemical features are responsible for the biological activity.
Homeopathic Preparations and Safety Testing
Bryonia alba is one of the most commonly prescribed homeopathic remedies, used by homeopaths for conditions including respiratory complaints, joint inflammation, and headaches. Homeopathic preparations involve serial dilutions far beyond the point where any original plant molecule is likely to remain in the final product, which is why these remedies are considered non-toxic by mainstream toxicology. Still, formal safety testing has been conducted. An acute and subacute toxicity study in Wistar rats found that B. alba in 6C, 30C, and 200C potentised dilutions caused no detrimental effects on body weight, food intake, blood parameters, or organ tissue at doses up to 2000 microliters per kilogram of body weight over 28 days.16Toxicology International. Preclinical Safety Evaluation of Potentised Ethanolic Dilutions of Bryonia alba : An Acute and Subacute Oral Toxicity Study in Wistar Rats
Separate research in immunosuppressed mice explored whether homeopathic dilutions of B. alba could modulate immune function. Mice whose immune systems had been suppressed with cyclophosphamide and then treated with B. alba in 6C and 200C dilutions showed improved hemoglobin, red blood cell, and white blood cell levels compared to untreated controls.17PLoS ONE. Modulatory action of Bryonia alba on the immune system in cyclophosphamide induced immunosuppression in BALB/c mice These are intriguing results, but they sit in a controversial area of research. The extreme dilutions used in homeopathy are well below the concentration at which conventional pharmacology would predict any molecular effect, and the broader scientific community remains skeptical about mechanisms that could explain activity at such dilutions. The mouse study is a peer-reviewed finding, but placing it in context means acknowledging that it does not settle the larger debate about how or whether ultra-dilute preparations work.
Bryonia and Its Specialist Bee
One of the more charming ecological stories in the Bryonia world involves Andrena florea, a solitary bee species that depends almost exclusively on Bryonia pollen to provision its larvae. In Poland, researchers found a positive relationship between the spread of B. dioica and the presence of A. florea, a bee that had previously been quite rare in the country.18Polish Journal of Entomology. Andrena florea Fabricius, 1793 (Hymenoptera, Apoidea, Apiformes): a rare bee species in Poland, related to the expansion of the alien plant Bryonia dioica Jacq. (Cucurbitaceae) As B. dioica expanded its range into new areas, A. florea followed it. This is an unusual twist on the invasive species narrative: an alien plant actively supporting the range expansion of a rare native pollinator with highly specific dietary requirements.
The relationship is obligate on the bee’s side. While Bryonia flowers are also visited by generalist pollinators, A. florea has evolved to specialize on Bryonia pollen and relies on it almost entirely. For the plant, the bee provides efficient pollination, particularly important for the dioecious species where pollen must physically travel from a male plant to a female one to produce fruit. The pair illustrates a broader ecological principle: specialist relationships can cross biogeographic boundaries, with consequences that are not always negative for the receiving ecosystem. In a landscape where pollinator decline is a major concern, the arrival of a new food resource that supports an otherwise declining bee species complicates the usual story about alien plants being unambiguously harmful.
Identifying Bryonia in the Field
If you are trying to identify Bryonia growing in your garden or along a trail, a few features help narrow it down. The leaves are palmately lobed, typically with five pointed lobes, and rough to the touch. The tendrils emerge from the stems at leaf nodes and coil tightly around anything they contact. Flowers are small, pale greenish-yellow or white, and in the dioecious species (B. dioica, B. alba) you will find male and female flowers on separate plants. Berry color is the quickest way to distinguish the two most widespread species: B. dioica produces bright red berries in clusters, while B. alba produces black berries.
In North America, the main species you are likely to encounter is B. alba, which has established invasive populations across several western states. In Europe, B. dioica is the more common hedgerow species in the west (Britain, France, Iberia), while B. alba is more prevalent in the north and east (Scandinavia, the Baltics, eastern Europe). If you find it growing in your yard, treat it with respect. Wear gloves when handling the plant, keep children and pets away from the berries, and if you plan to remove it, be prepared to dig deep: the root is the plant’s survival organ and will regenerate if left in the ground. Herbicide spot-treatments on freshly cut root stumps can improve kill rates, but check your local extension service for region-specific guidance on managing Bryonia as a weed.