Spearmint

Symptoms reported in cats

Most serious first.

1. 1
   Lethargy, weakness, uncoordinated gait (ataxia), tremors, and seizures While mild lethargy and weakness can occur from plant ingestion67, severe neurological signs like tremors, seizures, and severe lack of coordination are typically the result of exposure to concentrated spearmint essential oils.
2. 2
   Liver damage or liver failure Because cats lack the specific liver enzymes required to effectively process and metabolize plant essential oils, ingesting large amounts of spearmint leaves or even small amounts of spearmint essential oil can overwhelm and damage their liver.
3. 3
   Difficulty breathing, coughing, and sneezing These symptoms can be triggered by ingesting the toxic oils or simply by inhaling the strong, cool aromas of the mint plant and diffused spearmint oils, which irritate the feline respiratory tract.
4. 4
   Nausea, vomiting, diarrhea, and general upset stomach This is the most common reaction to nibbling fresh spearmint leaves12. The essential oils specific to garden mints have been known to relax the esophageal valve, which makes vomiting more likely to occur.
5. 5
   Skin irritation, redness, or burns on the lips, gums, tongue, or skin Direct physical contact with the mint plant or its concentrated essential oils can cause dermal irritation or burns, especially in hypersensitive cats.
6. 6
   Excessive drooling (hypersalivation) and difficulty swallowing Cats may drool or foam at the mouth after tasting the plant or being exposed to its essential oils.

Important notes

Spearmint (Mentha spicata) is a common garden herb. While chewing on a small amount of the fresh plant is unlikely to cause serious harm, it can lead to an upset stomach. The plant contains oils that are difficult for a cat's liver to process, which may cause vomiting or diarrhea. The real danger comes from spearmint essential oil, which is a highly concentrated form. Essential oils are much more potent than the plant itself and are toxic to cats. Exposure to the oil, whether by skin contact or ingestion, can lead to more severe symptoms, including potential liver stress if the exposure is significant or repeated. If your cat nibbles on a fresh spearmint leaf, they will likely only have mild digestive upset. However, keep all essential oils away from cats. If your cat eats a large amount of the plant or shows ongoing symptoms like vomiting or lethargy, it's best to contact your veterinarian.

• Toxic compounds: carvone, limonene, and related monoterpenoids; concentration is highest in the essential oil
• Mechanism: limited feline glucuronidation of monoterpenes leads to GI irritation and mild liver stress with repeated exposure
• Symptoms: vomiting, diarrhea, drooling, lethargy; usually mild and self-limiting with leaf exposure
• Spearmint essential oil is far more dangerous than the fresh plant — do not use on or near cats
• Contact your vet if your cat ingests large amounts or shows persistent symptoms