Is Pencil Cactus (Euphorbia tirucalli) Toxic to Cats?

Is pencil cactus toxic to cats?

Pencil cactus (Euphorbia tirucalli) is toxic to cats. The toxic principle is irritant and carcinogenic diterpene esters within the latex sap that causes oral, dermal and ocular irritation.

What is pencil cactus?

Family Euphorbiaceae
Botanical name Euphorbia tirucalli
Common names Pencil cactus, Sticks of fire, Milk bush, Indian tree spurge, Aveloz, Naked lady, Pencil tree, Firestick
Plant type Succulent, shrub
Flower colour Yellow
Native to Africa and Asia
Toxicity Toxic to cats
Toxic property Diterpene esters
Toxic parts All parts
Severity Moderate to severe

Pencil cactus is a member of the Euphorbiaceae genus, which contains over 2,000 species of trees, succulents and herbaceous plants. Euphorbia tirucalli is the scientific name for pencil cactus, a small tree shrub native to Africa and India. Its cactus-like leaves have a similar appearance to true cactus, minus the sharp needles. The plant is popular as an indoor plant due to its unique appearance and ease of care.

The stems break off easily if accidentally bumped or chewed, which will cause the plant to secrete a thick milky latex irritant sap.

Pencil plant irritant sap
Julia Wilson/Cat-World

Clinical signs


  • Intense oral pain
  • Vomiting
  • Drooling
  • Loss of appetite


  • Pain
  • Redness
  • Watery eyes
  • Photophobia
  • Ulceration
  • Temporary blindness


  • Pain
  • Papules
  • Redness
  • Swelling

First aid

If ocular exposure has occurred, flush the eye(s) immediately with water to remove as much sap as possible and then take the cat to a veterinary hospital.

Spot bathe the cat in cool water and dishwashing soap to remove irritant sap from the coat. Be extremely careful to not spread the sap to other areas of the body.

Oral exposure is generally self-limiting due to the immediate pain a cat will experience when chewing pencil cactus. Offer the cat a drink of something tasty such as tuna juice or milk to help dilute the toxin.


Toxicity is generally mild and self-limiting, but ocular exposure can cause extreme pain and temporary blindness and must be seen by a veterinarian. Permanent blindness has been reported in humans exposed to euphorbia sap due to secondary bacterial infection which highlights the importance of prompt medical intervention.

  • Ocular: Supportive management for ocular exposure can include irrigation, antibiotic ointment, and painkillers where necessary. The cat may benefit from a dark, quiet cage until the eyes have recovered.
  • Skin: Dermal exposure will require bathing to remove the toxin from the skin and coat which will also prevent cross exposure to the mouth or eyes during grooming.
  • Mouth: Oral exposure is generally self-limiting. If a large amount of plant has been consumed (extremely unlikely) and the cat is vomiting, the veterinarian may administer fluids to treat dehydration.


If you have pets, it is best to avoid pencil cactus or grow it in an area the cat cannot exercise. Euphorbia species are also toxic to people. Always wear protective eyewear and gardening gloves when handling pencil cactus. Irrigate well for dermal or ocular exposure and seek immediate medical attention.


  • Julia Wilson, 'Cat World' Founder

    Julia Wilson is the founder of Cat-World, and has researched and written over 1,000 articles about cats. She is a cat expert with over 20 years of experience writing about a wide range of cat topics, with a special interest in cat health, welfare and preventative care. Julia lives in Sydney with her family, four cats and two dogs. Full author bio