Periwinkle is one of the most versatile plants you’ll encounter, serving as a popular ground cover in landscaping, a source of two life-saving chemotherapy drugs, and the basis for brain-health supplements sold around the world. The name “periwinkle” actually refers to two related but distinct plants: Vinca minor (common periwinkle), a hardy ground cover native to Europe, and Catharanthus roseus (Madagascar periwinkle), the tropical species that revolutionized cancer treatment in the 1960s. Both have a long history in folk medicine, and both contain potent alkaloids that demand respect.
Landscaping and Ground Cover
Common periwinkle (Vinca minor) is widely planted as an evergreen ground cover, especially in mild climates. It produces small blue-violet flowers in spring and spreads into a dense, low mat that suppresses weeds and stabilizes soil. According to USDA guidance, it works best in partially shaded areas or north- and east-facing slopes, making it a go-to choice for spots under trees, along banks, and in odd corners of a yard where grass struggles. It tolerates full sun if it gets enough water, but shade is where it truly thrives.
Periwinkle handles light foot traffic but shouldn’t be planted where people walk regularly. Its low-maintenance nature is a big part of its appeal: once established, it needs little attention beyond occasional watering during dry spells. That said, it spreads aggressively in some regions, so check local guidelines before planting. Several U.S. states consider it invasive.
Cancer Treatment
The Madagascar periwinkle is the only known natural source of two powerful chemotherapy compounds: vincristine and vinblastine. These drugs were discovered almost by accident in the early 1950s, when Canadian researchers Robert Noble and Charles Beer were testing periwinkle extracts for their effect on blood sugar in rats. Instead of finding a diabetes treatment, they noticed the extracts dramatically lowered white blood cell counts, pointing toward potential cancer-fighting properties.
Vinblastine received FDA approval in 1961, followed by vincristine in 1963. Vincristine became a cornerstone of treatment for acute lymphoblastic leukemia (ALL), the most common childhood cancer, and remains part of standard therapy today. Vinblastine is used in regimens for Hodgkin lymphoma, certain brain tumors, and several adult cancers. In one real-world study of Hodgkin lymphoma patients treated with a vinblastine-containing regimen, the overall five-year survival rate was 95.4%, reaching 100% for early-stage patients.
These drugs work by disrupting cell division, which stops cancer cells from multiplying. That same mechanism, however, affects healthy cells too, which is why chemotherapy with these compounds can cause side effects like nerve tingling, nausea, and lowered immune function. Researchers continue working to increase the yield of these alkaloids from the plant, since they occur naturally in extremely small quantities.
Brain Health Supplements
A compound called vinpocetine, derived from an alkaloid found in common periwinkle, is sold widely as a supplement marketed for memory, focus, and cognitive sharpness. It works by widening blood vessels in the brain, increasing blood flow and helping brain cells take up more oxygen and glucose. This boost in cerebral metabolism is the basis for its reputation as a “brain supplement.”
Vinpocetine has been prescribed as a pharmaceutical drug in parts of Europe for decades, primarily for age-related cognitive decline and certain types of cerebrovascular conditions. In the United States, its legal status is murkier. The FDA published a notice in 2016 stating that vinpocetine likely does not qualify as a dietary ingredient and may be excluded from the definition of a dietary supplement, since it was investigated as a drug before it was ever sold as a supplement. Despite this, vinpocetine products remain widely available in U.S. stores and online.
If you’re considering vinpocetine, know that while the biological mechanisms are well-documented in laboratory and animal studies, large-scale clinical trials in humans are limited. Its blood-vessel-relaxing effects extend beyond the brain to peripheral blood vessels, which means it can lower blood pressure. That’s worth keeping in mind if you already take blood pressure medication.
Traditional and Folk Medicine
Long before scientists isolated its alkaloids, periwinkle was a staple of folk medicine across multiple cultures. Preparations made from the plant were used to treat diabetes, high blood pressure, hemorrhage, insect stings, eye inflammation, and even cancers. In many tropical regions, people brewed teas or decoctions from the leaves, which were also used as disinfectants for wounds.
Lab studies have confirmed that extracts from Catharanthus roseus do show antimicrobial activity. Leaf extracts, in particular, demonstrated significantly stronger antibacterial effects than extracts from stems, roots, or flowers. Antifungal activity has been documented both in the lab and in animal studies. None of these uses, however, have been validated in human clinical trials, so the traditional applications remain just that: traditional, not evidence-based in a modern clinical sense.
Toxicity in Humans
Periwinkle is not safe to consume raw or as a homemade preparation. The same alkaloids that make it valuable in medicine can cause serious harm when ingested without careful dosing. A published case report describes a 65-year-old woman who ate Catharanthus roseus and arrived at the emergency department with severe abdominal pain, fever, loss of appetite, and numbness in her lower legs. She developed gastric ulcers from the plant’s alkaloids damaging her stomach lining.
The full spectrum of toxicity from periwinkle ingestion includes bone marrow suppression (which cripples the immune system), gastrointestinal damage, nerve damage causing numbness or tingling, mouth sores, fever, and in severe cases, multi-organ failure. An animal poisoning case in sheep showed significant changes in blood clotting, kidney function markers, and calcium levels. These are not mild reactions. Eating this plant is genuinely dangerous.
Toxicity in Pets
Periwinkle is toxic to dogs, cats, and horses. The ASPCA lists it as poisonous due to its vinca alkaloid content. Signs of poisoning in pets include vomiting, diarrhea, low blood pressure, depression, tremors, seizures, coma, and potentially death. If you grow periwinkle as ground cover and have pets that chew on plants, consider placing it in areas your animals can’t access.