The symptoms of running myrtle poisoning range from moderate to severe, and correlate directly to the amount ingested. If your cat has ingested the running myrtle in any quantity, seek veterinary attention immediately.

The running myrtle plant, more commonly known as periwinkle, is a member of the Apocynaceae family. Recognize the running myrtle by its dark green, waxy leaves and star-shaped purple flowers. This plant contains vinca alkaloids. Vinca alkaloids have chemotherapeutic effects in human medicine, but are toxic to cats, dogs, and horses when ingested.

Symptoms of running myrtle are usually rapid onset, appearing within two hours following ingestion. If you notice any of the following symptoms, consult your vet immediately:

The following serious symptoms are associated with ingestion of larger quantities. 

The running myrtle is known by several different names, including:

The cause of running myrtle poisoning in cats is ingestion. Ingesting small quantities of the running myrtle will usually cause moderate symptoms, particularly gastrointestinal signs and depression. Ingesting larger quantities will result in more serious symptoms. Cats do not usually ingest large quantities of any poisonous plants because symptoms typically manifest rapidly. At present, it is unclear which parts of the plant contain the highest concentration of vinca alkaloids. No matter how much or which part of the plant your cat has ingested, you should seek the help of a veterinary professional. Owners can never know the true extent of poisoning even if symptoms appear to be mild.

If your cat is exhibiting serious symptoms, it may be a good idea to call your vet before you arrive. This will help them prepare to treat an emergency case of running myrtle poisoning. If the running myrtle is a flower you’ve purchased or grown in your garden, take a sample with you when you go to the vet. Tell your vet how long your cat has been experiencing symptoms, as well as approximately how much of the plant your cat ingested, if you know.

Taking blood and urine tests is standard procedure for diagnosing plant poisoning, and will usually confirm the diagnosis. If severe symptoms are present, other tests including CT scans and x-ray may be utilized.

Mild cases of running myrtle poisoning are usually treated with standard treatment methods for plant poisoning. Inducing vomiting, followed by administering activated charcoal, will help clear and absorb any undigested toxins in the stomach respectively. Intravenous fluid therapy is almost always used in cases of plant poisoning to correct fluid imbalances caused by vomiting and diarrhea. If vomiting is persistent, antiemetics may be administered.

Severe cases of running myrtle poisoning will be treated on a symptomatic basis. Your cat may need to be hospitalized in order to recover, particularly if they have experienced seizures or are comatose. Your vet will monitor organ function during hospitalization, and will recommend a personalized treatment and recovery plan based on your cat’s specific needs.

Recovery and prognosis for mild cases of running myrtle poisoning usually range from good to excellent as long as the poisoning is diagnosed and treated quickly. Cats suffering from mild bouts of plant poisoning usually recover fully with 24 hours following treatment. Severe cases may have a more guarded prognosis.

Follow-up appointments are generally not required for mild cases of running myrtle poisoning. Your vet may schedule follow-up appointments as needed if your cat is presenting serious symptoms. During these appointments, your vet will monitor neurological function and healing progress.

Cats often encounter poisonous plants through outdoor activity. If this was the case for your cat, it may be a good idea to reduce or monitor their outdoor activity to avoid future cases of plant poisoning.