Vinca minor
Apocynaceae
Creeping Myrtle; Lesser Periwinkle; Dwarf Periwinkle; Small Periwinkle; Common Periwinkle; Periwinkle; Running Myrtle; Bowles Periwinkle; Myrtle; Vinca; Vinca minor
Vinca alkaloids and related indole alkaloids, including vindoline, vincadifformine, vincamine, perivincine, reserpine, akuammine, alstonine, ajmalicine, vinine, vinomine, vinoxine, vintsine, leurosine, and related Vinca constituents; saponins and other gastrointestinally active plant compounds may also be present. Some older or broader “vinca” references include vincaleukoblastine, vinblastine, leurocristine, vincristine, and related compounds more strongly associated with Madagascar Periwinkle, Catharanthus roseus, so Vinca minor should be treated as toxic but not automatically equated with the more medically potent Catharanthus profile.
Gastrointestinal upset, vomiting, diarrhea, abdominal pain, drooling, reduced appetite, depression, lethargy, weakness, hypotension, low blood pressure, possible cardiac abnormalities, tremors, loss of coordination, seizures, progressive weakness or paralysis, coma, and death in severe cases. Serious intoxication of animals from ordinary Vinca minor ingestion appears exceedingly rare, and fatal intoxication is rarer still, with most pet exposures expected to involve gastrointestinal upset unless a large amount or concentrated preparation is consumed.
Creeping Myrtle, Vinca minor, more commonly known as Lesser Periwinkle, Dwarf Periwinkle, Small Periwinkle, Common Periwinkle, Running Myrtle, Bowles Periwinkle, or simply Periwinkle, is an evergreen trailing vine or mat-forming groundcover in the dogbane family, Apocynaceae. It spreads along the ground, rooting at the nodes and forming dense carpets of glossy, dark green foliage. A single plant can gradually cover a considerable area, especially in shaded woodland gardens, slopes, borders, and old landscape beds.
The leaves are generally oval to heart-shaped, opposite, glossy, and dark green, growing in pairs along the length of the stem. The flowers are borne singly in the leaf axils on ascending stems and are typically blue-violet to lavender, funnel-shaped, five-petaled, and roughly one to two inches across. Small Periwinkle flowers heavily throughout the spring and may bloom sporadically during the summer.
This plant is widely cultivated as a flowering ornamental groundcover because it is hardy, shade-tolerant, evergreen in many climates, and capable of quickly stabilizing soil. Those same traits can make it aggressive or invasive in some regions, where it escapes cultivation and forms dense mats that crowd out native understory plants. From a pet-safety perspective, its common use as groundcover means dogs, cats, horses, and other animals may encounter it in yards, gardens, wooded edges, and older landscaped areas.
A distinction should be made between Vinca minor, Creeping Myrtle or Lesser Periwinkle, and Catharanthus roseus, Madagascar Periwinkle, which is also commonly called Vinca in garden centers. Both plants belong to the broader Apocynaceae toxic-alkaloid world, and both are often discussed under the common name “vinca,” but they are not the same plant. Catharanthus roseus is the plant most strongly associated with the medically important anticancer alkaloids vinblastine and vincristine. Vinca minor contains its own broad array of indole alkaloids and should still be treated as toxic, but ordinary pet exposure to Creeping Myrtle should not automatically be treated as identical to ingestion of Madagascar Periwinkle or concentrated vinca alkaloid preparations.
Information regarding the specific toxicity of Vinca minor varies from source to source, although sources generally agree that the plant contains an extensive array of alkaloids. It may also contain saponins and various other compounds capable of producing gastrointestinal irritation. The alkaloid content may vary by region, growing conditions, plant part, and whether the plant is grown as a perennial groundcover or under different cultivated conditions.
Of the many compounds reported from Vinca minor, principal or notable components include vindoline, vincamine, and vincadifformine, along with additional alkaloids such as akuammine, perivincine, reserpine-type compounds, ajmalicine, vinine, vinomine, vinoxine, and related constituents. Many of these alkaloids are biologically active, and some have hypotensive or vascular effects. The practical concern with ingestion is therefore gastrointestinal upset, possible lowering of blood pressure, depression, weakness, tremors, or, in extreme cases, neurologic or cardiac signs.
Current plant databases generally frame Vinca minor as a low-severity poisonous plant. That matches the practical pattern seen in the available animal-exposure discussion: serious intoxication appears uncommon, and fatal intoxication is rarer yet. The plant is generally not palatable to most animals, and large ingestions appear to be unusual. Most dogs, cats, horses, or livestock would not be expected to consume large quantities voluntarily unless food choices were limited, plant material was mixed into feed, or the animal was unusually curious or prone to eating plants.
When ingested, the overall effect of these compounds may include irritation of the stomach and intestines, vomiting, diarrhea, abdominal discomfort, depression, weakness, and reduced blood pressure. In exceptionally large doses, systemic paralysis, severe neurologic signs, or death are theoretically possible. This is why the plant should not be treated as safe, even though it should also not be exaggerated into one of the most dangerous plants in the database.
Creeping Myrtle also has a long history of medicinal and folk use, which further complicates how people interpret its safety. Plants with medicinal use are often biologically active by definition. The fact that a plant has been used historically does not mean a dog, cat, horse, or other animal can safely chew it in raw, uncontrolled amounts. Intentional human use, extracts, herbal preparations, and pharmaceutical alkaloids are very different from a pet eating raw groundcover.
The most likely pet exposure involves a dog chewing or swallowing leaves while outdoors, a puppy investigating garden beds, or a pet eating plant material during yardwork. Cats are less likely to consume a large amount, but cats that chew plants should still be kept away from it. Horses and livestock are not expected to seek it out as forage, but they should not be allowed to consume large amounts of any vinca-containing landscape material or clippings.
For practical safety, Creeping Myrtle should be considered capable of causing mild to moderate gastrointestinal upset and, in larger exposures, possible hypotension or neurologic signs. Life-threatening intoxication in animals is exceedingly rare, but persistent vomiting, diarrhea, weakness, tremors, collapse, seizure activity, or suspected large ingestion should be handled as a veterinary concern.
Immediate Response to Creeping Myrtle Ingestion
- Remove the Source: Prevent further ingestion by removing the pet or grazing animal from Creeping Myrtle, Periwinkle, groundcover beds, vines, leaves, stems, flowers, clippings, or any remaining plant material.
- Identify the Plant: Determine whether the plant is Vinca minor, Creeping Myrtle or Lesser Periwinkle, or whether it may be Catharanthus roseus, Madagascar Periwinkle, which has a different and potentially more serious alkaloid profile.
- Remove Plant Material from the Mouth: If ingestion was recent and it is safe to do so, remove visible plant material from the mouth.
- Rinse the Mouth: Flush the mouth gently with water to remove remaining plant material, sap, or irritating residue.
- Watch for Symptoms: Monitor for vomiting, diarrhea, abdominal pain, drooling, reduced appetite, depression, weakness, lethargy, tremors, loss of coordination, low blood pressure, collapse, or seizures.
- Contact Veterinary Help if Needed: Consult a veterinarian, emergency veterinary clinic, Pet Poison Helpline, or another animal poison-control professional if a large amount was eaten, if the plant identity is uncertain, if symptoms are persistent or severe, or if the exposed animal is very small, young, elderly, pregnant, medically fragile, or already ill.
Inducing Vomiting and Decontamination
- Usually Low-Severity Exposure: Life-threatening intoxication from ordinary Vinca minor ingestion is exceedingly rare, and most cases are expected to involve gastrointestinal upset rather than severe poisoning.
- Getting Plant Material Out Matters: If a dog has recently swallowed a meaningful amount of Creeping Myrtle leaves, stems, or flowers, removing remaining plant material from the stomach may reduce continued gastrointestinal irritation and alkaloid exposure.
- Spontaneous Vomiting May Occur: The pet may vomit naturally as the body attempts to expel bitter, irritating, non-digestible plant material.
- Inducing Vomiting in Dogs Only: If ingestion was recent and the dog is alert, breathing normally, able to swallow, and not showing weakness, collapse, repeated vomiting, severe depression, breathing difficulty, tremors, seizures, loss of coordination, abnormal heart signs, or neurologic signs, a veterinarian or animal poison-control professional may recommend inducing vomiting with fresh 3% hydrogen peroxide.
- Cat Warning: Hydrogen peroxide should not be used to induce vomiting in cats unless a veterinarian specifically directs it. Cats are more prone to irritation and complications from hydrogen peroxide, and home vomiting attempts may create more risk than benefit.
- Do Not Induce Vomiting in an Unstable Animal: Vomiting should not be attempted in any animal that is weak, collapsed, sedated, having trouble breathing, unable to swallow normally, already vomiting repeatedly, showing tremors, seizures, abnormal heart signs, low blood pressure, or neurologic signs.
- Activated Charcoal: Activated charcoal may be considered by a veterinarian or poison-control professional in unusually large, concentrated, or clinically significant ingestion cases, but ordinary Creeping Myrtle exposures rarely require aggressive decontamination.
- Gastric Lavage: If a very large amount was ingested or if severe signs are developing, a veterinarian may consider gastric lavage or additional decontamination in a controlled setting.
Symptomatic Care and Treatment
- No Specific Antidote: There is no specific antidote for Periwinkle or Creeping Myrtle ingestion. Treatment is symptomatic and supportive.
- Hydration: Ensure the pet receives adequate fluids to reduce the risk of dehydration caused by vomiting or diarrhea.
- Monitor Vomiting and Diarrhea: Repeated vomiting, persistent diarrhea, blood in stool, inability to keep water down, weakness, or worsening lethargy should prompt veterinary evaluation.
- Blood Pressure and Cardiac Monitoring: In larger ingestions or symptomatic animals, a veterinarian may monitor blood pressure, heart rate, rhythm, perfusion, and general cardiovascular status because some Vinca alkaloids may have hypotensive or cardiac effects.
- Neurologic Monitoring: Tremors, loss of coordination, weakness, progressive paralysis, seizures, collapse, or coma require emergency veterinary evaluation and supportive care.
- Gastrointestinal Protection:
- Kapectolin: To alleviate gastrointestinal upset and diarrhea, Kapectolin may be given at a dose of 1 to 2 ml/kg four times daily to help coat and protect the stomach lining.
- Sucralfate: Sucralfate may be used for gastrointestinal irritation because it reacts with stomach acid to form a paste-like protective barrier between irritated tissue and stomach contents.
- Dogs greater than 60 lbs: 1g every 6 to 8 hours.
- Dogs less than 60 lbs: 0.5g every 6 to 8 hours.
- Cats: 0.25g every 8 to 12 hours.
Groundcover and Landscape Prevention
- Keep Pets Out of Dense Beds: Dense mats of Creeping Myrtle can hide chewed leaves, clippings, and plant debris. Keep plant-chewing pets away from established groundcover beds.
- Clean Up Yard Waste: Do not leave freshly pulled or cut Vinca material where dogs, puppies, livestock, or other animals can chew it.
- Do Not Feed Clippings: Landscape clippings or pulled groundcover should not be fed to horses, goats, sheep, cattle, rabbits, or other animals.
- Confirm Plant Identity: Because “vinca” and “periwinkle” may refer to different plants, confirm whether the exposure involved Vinca minor, Vinca major, or Catharanthus roseus.
Prognosis and Recovery
- General Outlook: Serious intoxication of animals from Creeping Myrtle is exceptionally rare, and fatal intoxication is rarer yet.
- Expected Recovery: In most cases, symptoms are expected to be limited to gastrointestinal upset, including vomiting and diarrhea, with recovery after supportive care and prevention of further ingestion.
- Higher-Risk Cases: Prognosis becomes more guarded if the animal consumes a large amount, develops low blood pressure, tremors, seizures, progressive weakness, paralysis, cardiac abnormalities, coma, or cannot maintain hydration.
- Veterinary Care: Veterinary evaluation is recommended when symptoms are persistent, severe, neurologic, cardiovascular, or when the plant identity is uncertain.
- Prevention: Prevent further ingestion of the plant, keep Creeping Myrtle and other vinca groundcovers away from pets that chew plants, and remove clippings from animal-accessible areas.