Erukku (Calotropis gigantea): names, uses, safety

Erukku, aak in Hindi, is giant milkweed or crown flower, a large shrub of waste ground with waxy lavender or white flowers, each with a neat central crown. Erukkam poo garlands are offered to Ganesha, especially on Vinayaka Chaturthi, and the flowers are strung into leis in Hawaii and garlands in Thailand. All parts are full of caustic, poisonous latex. A smaller cousin of drier country, Calotropis procera, has its own page.

Botanical name: Calotropis gigantea (L.) W.T.Aiton
Family: Apocynaceae
Tamil: Erukku
Hindi: Aak
Sanskrit: Arka
Parts used: Latex in lists, Leaves in lists, Flowers in ceremony
Habit: Giant milkweed with a crown flower and caustic latex
Last updated: 2026-10-27

How to recognise Erukku

It is a large shrub, often two to four metres tall, with pale, corky bark and abundant milky latex.

The leaves are thick, grey-green, waxy and broadly oval, clasping the stem in opposite pairs.

The flowers are lavender or white, with five spreading, pointed petals and a raised, crown-like centre.

The fruits are large, curved, inflated pods that release seeds with silky floss.

Calotropis procera has smaller flowers with upright petals.

Traditional use of Erukku

Ritual

Erukkam poo garlands are offered to Ganesha, and the leaves are used in Ratha Saptami baths in Tamil Nadu.

Tamil ritual practice

Household

The bark fibre is strong and was twisted into bowstrings and fishing lines.

Indian village practice

Ayurveda

Arka leaves are warmed and laid on painful joints, and the latex appears in a few external formulas.

Ayurvedic practice

Modern notes on Erukku

The latex contains cardenolides and protein-digesting enzymes, which make it toxic and caustic.

Latex in the eye causes painful corneal injury, often from pruning or children playing with the plant.

Plain tiger and monarch butterfly caterpillars feed on it and store its toxins.

Erukku safety

Never take any part by mouth or let latex near the eyes. If latex enters the eye, rinse with running water for fifteen minutes and see a doctor.

Ecology and sourcing

It grows across South and South-east Asia and southern China on dry, disturbed ground.

Carpenter bees pollinate the flowers.

Few animals eat it, so it thrives on grazed land.

Related plants

Also in Apocynaceae

Questions about Erukku

Why is Erukku called crown flower?

Each flower has a crown-like centre.

Is Erukku poisonous?

Yes. Its latex is toxic and caustic.

Why is Erukku offered to Ganesha?

It is a traditional offering, especially on Vinayaka Chaturthi.

How is Erukku different from Calotropis procera?

It is larger, with bigger, spreading flowers.

Which butterflies use Erukku?

Plain tiger and monarch caterpillars.

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.