Kattamanakku, physic nut, is a shrub from Mexico and Central America planted as a hedge across dry India because cattle will not eat it. In the 2000s India promoted it on wasteland as a biodiesel crop, but yields fell far short and most plantations were abandoned. Its seeds look like nuts and taste pleasant, but they are poisonous and often poison children. Hindi ratanjot also names other red-dye plants.
- Botanical name
- Jatropha curcas L.
- Family
- Euphorbiaceae
- Tamil
- Kattamanakku
- Hindi
- Ratanjot
- Parts used
- None as food
- Habit
- Physic-nut hedge shrub; the seeds are poisonous
- Last updated
- 2026-10-27
How to recognise Kattamanakku
It is a soft-wooded shrub or small tree, usually three to five metres tall, with thick, grey, smooth branches that ooze sap when cut.
The leaves are broad, long-stalked and shallowly three- to five-lobed, with a heart-shaped base.
Small greenish-yellow flowers grow in loose clusters at the branch tips.
The fruit is a round capsule that turns yellow and then black, holding about three black seeds two centimetres long.
Castor, Ricinus communis, has deeply cut, star-shaped leaves and spiny capsules.
Traditional use of Kattamanakku
Farming
Cuttings root easily and are planted as living fences around fields and cattle pens.
Indian farm practice
Household
The seed oil was burned in lamps and used to make soap in parts of Africa and Asia.
African and Asian household practice
Industry
India’s national biodiesel mission of the early 2000s planned jatropha on millions of hectares of wasteland.
Indian energy policy history
Modern notes on Kattamanakku
The seeds are about one-third oil, which can be converted to biodiesel.
Field yields on poor, dry land were much lower than early estimates, which ended most large plantings in India and Africa.
The seeds contain curcin, a toxic protein, and phorbol esters, which cause vomiting, diarrhoea and dehydration.
A few seeds can make a child seriously ill, and cases are reported every year in rural India.
Kattamanakku safety
Never eat the seeds. If a child has eaten any, take them to a hospital at once. Keep the plant away from school yards and play areas, and wash off the sap, which irritates skin.
Ecology and sourcing
It is native to Mexico and Central America and was spread worldwide by Portuguese traders.
It survives drought by dropping its leaves.
It can spread from seed into dry grassland and is invasive in parts of Australia.
Related plants
Also in Euphorbiaceae
Questions about Kattamanakku
Are physic nuts edible?
No. They are poisonous.
Why was Kattamanakku planted for biodiesel?
Its oily seeds can be made into fuel.
Did the biodiesel plan work?
Mostly not; yields were too low.
How is Kattamanakku different from castor?
Castor has star-shaped leaves and spiny fruit.
Why is Kattamanakku used as a hedge?
Animals avoid it and cuttings root easily.
Sources
- Jatropha curcas L. — Plants of the World Online, Kew (search) (accessed 2026)
- Wikidata item Q74644 (Jatropha curcas)
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.