Catharanthus roseus, commonly known as the Madagascar periwinkle, is a perennial flowering plant in the Apocynaceae family. It is widely used as an ornamental plant due to its attractive, star-shaped flowers, which come in a variety of colours. The most common variety is bright pink with a slightly darker centre. Beyond its aesthetic appeal, this plant is also valued for its significant medicinal properties, as it contains the alkaloids vincristine and vinblastine, which are used in chemotherapy for cancers such as leukaemia and lymphoma.

Although reports of companion animals ingesting this plant are uncommon, Madagascar periwinkle has the potential to cause poisoning if ingested. In cattle and sheep, repeated ingestion over several days has been associated with neurological signs such as unsteadiness and tremors. Other possible effects include hypotension (low blood pressure), bradycardia (slow heart rate), and hypoglycaemia (low blood sugar). Because of its chemotherapeutic properties, ingestion may also lead to bone marrow suppression; however, this risk is not well characterised in animals.

While it is not necessary to remove this plant from the home, pet owners should be mindful to:

✅ Keep toxic plants in areas that are inaccessible to pets, such as on high shelves, in hanging baskets, or on tall stands.

✅ Be cautious with clippings and dispose of plant debris in a secure outdoor bin away from your pet.

✅ Provide alternative safe greens, such as pet grass, to redirect chewing behaviour.

Ensuring the wellbeing of your pet is paramount, but veterinary care for poisoning can be costly. Toxic plant exposures may require diagnostics, hospitalisation, or even specific antidotes. Pet insurance can provide peace of mind and financial protection in these events. The Animal Poisons Helpline is proudly sponsored by Bow Wow Meow Pet Insurance, which is currently offering two months of their Nose-to-Tail Cover free during the first year for Helpline followers. Visit quote.bowwowinsurance.com.au for more information.

The Animal Poisons Helpline provides free expert advice to pet owners in Australia and can be reached on ☎️ 1300 869 738 (AU), 0800 869 738 (NZ) , 3106 4216 (SG), (917) 722-5958 (US) or +1917-722-5958 (CAN).

If you suspect your pet has ingested Madagascar periwinkle or any other poisonous plant, contact your veterinarian or the Animal Poisons Helpline immediately. If you’re a veterinary professional, we invite you to join our Animal Poisons Centre For Vets Facebook group, which is regularly updated with toxicology tips and emerging trends in animal poisonings.