Pennyroyal Oil Poisoning in Cats

Pennyroyal poisoning is a rare, life-threatening condition that occurs as the result of exposure to pennyroyal oil and must be treated as an emergency as it can cause life-threatening liver damage at very low doses.

No amount of pennyroyal oil should be considered safe for cats.

If ingestion is known or suspected, immediate veterinarian attention is crucial in increasing the animal's chances of survival.

Clues to suggest pennyroyal poisoning include:

• The smell of essential oil on the animal's breath
• Scent on skin
• The smell of essential oil in vomit

Ingestion of pennyroyal oil can also cause anemia.

Pennyroyal oil poisoning is caused by exposure to a toxic dose of Pennyroyal essential oil. This essential oil is derived from the pennyroyal mint plants Mentha pulegium and Hedeoma pulegioides and is a common ingredient in a number of anti-parasitic and fleas ointments, powders, and sprays.

Toxicosis can occur as the result of accidental exposure or the incorrect use of anti-parasitic and flea medications.

Cats spend large parts of their day grooming; therefore, the application of pennyroyal oil-containing products on any part of their body can result in ingestion and resulting toxicosis.

No dose should be considered safe for cats.

If exposure to pennyroyal oil is witnessed, the diagnosis is self-evident. Ingestion can occur without a witness but leaves evidence such as mint-scented breath, vomit, and coat.

A cat presenting symptoms of pennyroyal toxicosis generally undergoes the following diagnostics:

• Blood tests: blood tests do not identify the presence of toxins but are useful in assessing the severity of the toxicosis
• Physical examination
• History of exposure

Early treatment focuses on decontamination and stabilization. Treatment options include:

Early decontamination

• Gastrointestinal decontamination: via induced vomiting, or gastric lavage Note: Induction of vomiting or administration of activated charcoal should only be performed by a veterinarian. There is no safe way to induce vomiting or administer activated charcoal at home.
• Activated charcoal
• Skin decontamination: washing with a mild shampoo is recommended to eliminate traces of pennyroyal from the animal's coat

Symptomatic and subsequent treatment

• N-acetylcysteine
• IV fluid therapy
• Liver protectant drugs
• Gastrointestinal protectant drugs
• Antiemetic medication
• Blood transfusion: If the condition leads to life-threatening anemia, a blood transfusion is the best way to keep the cat alive
• Supplemental oxygen: anemia causes a decrease in oxygen levels in the animal's system
• Vitamin K supplementation to aid in clotting

Prognosis of pennyroyal oil poisoning varies from guarded to extremely poor and is dependent on the timing of treatment and severity of liver damage.

If medical attention is delayed or the condition is left untreated, most affected animals die shortly after ingestion.

Pennyroyal poisoning is not contagious.

Even though pennyroyal poisoning is not contagious, the presence of essential oils on an animal's coat can cause other cats in the house to develop symptoms due to grooming.

Prevention strategies include:

• Precaution in applying flea products
• Checking ingredient lists in flea products
• Follow label instructions
• Diligent storage of essential oils

Pennyroyal poisoning is a rare condition in cats.

Typical treatment of pennyroyal oil poisoning may include:

• Gastrointestinal decontamination
• Skin decontamination
• IV fluid therapy
• Liver protectant drugs
• Gastroprotectant drugs