Nithyakalyani (Catharanthus roseus)

Nithyakalyani, sadabahar in Hindi, is the Madagascar periwinkle, a tough garden plant that flowers pink or white all year. In the 1950s researchers studying its folk use for diabetes found instead the alkaloids vinblastine and vincristine, which became important chemotherapy drugs for leukaemia and lymphoma. Those drugs are given in hospitals in exact doses. The plant itself is poisonous to eat.

Botanical name: Catharanthus roseus (L.) G.Don
Family: Apocynaceae
Tamil: Nithyakalyani
Hindi: Sadabahar
Parts used: None for home use
Habit: Garden periwinkle; its alkaloids are hospital drugs, not home remedies
Last updated: 2026-10-27

How to recognise Nithyakalyani

It is a low, bushy perennial, usually knee-high, with glossy, oval, dark green leaves in opposite pairs.

The flowers have five flat petals, pink, white or white with a red eye, on a slender tube.

It flowers through the year, which is behind the names sadabahar and nithyakalyani, ever-blooming.

The fruit is a pair of slender pods with small black seeds.

True periwinkles, Vinca, are trailing plants of cooler climates.

Traditional use of Nithyakalyani

Garden

It is planted along borders, in pots and on graves because it flowers continuously with little water.

Indian garden practice

Folk use

Leaf decoctions were used in folk practice in several countries for diabetes.

Folk practice in Madagascar, the Caribbean and Asia

Modern notes on Nithyakalyani

Researchers at the University of Western Ontario and Eli Lilly isolated vinblastine and vincristine in the late 1950s.

The plant contains more than a hundred alkaloids, and the useful ones occur in tiny amounts.

Studies did not confirm a reliable effect on blood sugar.

Vinca alkaloids damage nerves and bone marrow, which is why they are given only under oncologists.

Nithyakalyani safety

Do not drink leaf or flower decoctions or chew the plant, especially for diabetes; it is toxic. Keep children and pets from eating it.

Ecology and sourcing

It is native to Madagascar, where its wild relatives are endangered.

It has spread to waste ground and coasts throughout the tropics.

Butterflies and moths visit its flowers.

Related plants

Also in Apocynaceae

Questions about Nithyakalyani

Is periwinkle a cure for diabetes?

No. Studies did not confirm it, and the plant is toxic.

Which drugs come from Nithyakalyani?

Vinblastine and vincristine, used in chemotherapy.

Is Nithyakalyani safe in the garden?

Yes, if no one eats it.

Why is Nithyakalyani called sadabahar?

It flowers all year.

Where is Nithyakalyani from?

Madagascar.

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.