Pencil cactus (Euphorbia tirucalli)

Thirukalli, also called pencil tree or milk bush, is a leafless African spurge with bundles of green, pencil-thin stems. Tamil villages plant it as a hedge because cattle and goats leave it alone. Every part is full of a white latex that burns skin and can badly damage eyes. In the 1980s the chemist Melvin Calvin promoted it as a possible source of petroleum-like fuel.

Botanical name: Euphorbia tirucalli L.
Family: Euphorbiaceae
Tamil: Thirukalli
Hindi: Pencil cactus
Parts used: None in the kitchen
Habit: Pencil-stemmed African spurge planted as a village hedge; the latex is a hazard
Last updated: 2026-10-27

How to recognise Pencil cactus

It is a shrub or small tree, up to several metres tall, made of masses of smooth, green, cylindrical branches about as thick as a pencil.

Tiny, narrow leaves appear on new growth but fall quickly, so the plant looks leafless.

Small yellow-green flower clusters form at the tips of branches.

Any break in the stem oozes thick, white, milky latex.

Cactus look-alikes have spines; thirukalli has none.

Traditional use of Pencil cactus

Farming

It is planted as a living fence around fields and homesteads in dry Tamil Nadu and across East Africa, because animals avoid it.

Tamil and East African farm practice

Folk use

In parts of Africa the latex has been used as a fish poison and as a glue, and the stems as fuel.

African folk practice

Garden

A red-stemmed cultivar, known as firesticks, is sold as an ornamental succulent.

Garden trade practice

Modern notes on Pencil cactus

The latex contains phorbol esters that inflame skin and eyes and can promote tumours in laboratory tests.

Researchers have studied whether frequent exposure to its latex in East Africa activates Epstein–Barr virus and raises the risk of Burkitt lymphoma.

Eye splashes from pruning cause painful inflammation of the cornea and have led to lasting vision loss.

The latex is rich in hydrocarbons, which is why it was studied as a fuel crop.

Pencil cactus safety

Wear gloves and eye protection when cutting it. If latex gets in the eye, rinse with running water for at least fifteen minutes and see a doctor the same day. Keep children and pets from breaking the stems, and do not take it by mouth.

Ecology and sourcing

It is native to eastern and southern Africa and has been planted across the tropics.

It survives long droughts because its green stems do the work of leaves.

Few grazing animals touch it, so it can spread on overgrazed land.

Related plants

Also in Euphorbiaceae

Questions about Pencil cactus

Is Pencil cactus a cactus?

No. It is a spurge, family Euphorbiaceae.

Is the latex dangerous?

Yes. It burns skin and can seriously injure eyes.

What should I do if Pencil cactus gets in my eye?

Rinse for fifteen minutes and see a doctor promptly.

Why is Pencil cactus used as a hedge?

Livestock avoid it, and it needs almost no water.

Is Pencil cactus safe for pets?

No. Keep pets from chewing it.

Sources

Educational page about a plant. It is not medical advice, not a diagnosis, and not an offer to sell. Traditional use is historical. If you need care, ask a licensed clinician. Questions: hello@meevamed.com.