Kattu valli (Dioscorea bulbifera)

Kattu valli is air potato, a twining yam that grows potato-like bulbils in its leaf axils. Some cultivated forms are boiled and eaten, but wild bitter forms are toxic and have caused liver damage when used as herbal medicine. In tribal India the bulbils are eaten only after repeated boiling. It has become a serious invasive vine in Florida. Hindi ratalu and Tamil senai are used for more than one yam.

Botanical name: Dioscorea bulbifera L.
Family: Dioscoreaceae
Tamil: Kattu valli
Hindi: Ratalu
Sanskrit: Vārāhī
Parts used: Aerial bulbil after known processing, Tuber in lists
Habit: Air-potato yam; wild bitter forms are toxic
Last updated: 2026-10-27

How to recognise Kattu valli

It is a fast-growing twining vine that climbs high into trees and dies back in the dry season.

The leaves are alternate, heart-shaped and long-pointed, with prominent curved veins running from the base to the tip.

Round to angular, brownish, warty bulbils, from marble to fist size, form in the leaf axils.

The underground tuber is small or missing in many forms.

Greater yam, Dioscorea alata, has winged, square stems and opposite leaves.

Traditional use of Kattu valli

Kitchen

Edible forms are peeled, sliced and boiled several times, throwing away the water, before cooking.

Indian tribal and African food practice

Chinese medicine

The dried tuber, huang yao zi, has been used in Chinese herbal medicine for goitre and swellings.

Chinese herbal practice

Modern notes on Kattu valli

Wild forms contain diosbulbin B and other compounds that have caused liver injury in people using the plant as medicine.

Bitterness is a warning sign of these toxins.

In Florida a leaf beetle from its native range was released in 2012 to control the invasive vine.

Kattu valli safety

Never eat bulbils or tubers raw, and do not eat any that taste bitter. Eat only known edible forms after repeated boiling with the water thrown away, and do not use the plant as a herbal medicine.

Ecology and sourcing

It is native to tropical Asia, Africa and northern Australia.

Bulbils drop and sprout into new vines, so it spreads quickly.

In Florida and elsewhere it smothers native trees and shrubs.

Related plants

Questions about Kattu valli

Is air potato edible?

Only certain forms, and only after thorough boiling.

Why is Kattu valli called air potato?

It grows potato-like bulbils on the vine.

Can Kattu valli harm the liver?

Yes. Wild forms used as medicine have caused liver injury.

How is Kattu valli different from greater yam?

Greater yam has winged stems and opposite leaves.

Is Kattu valli invasive?

Yes, in Florida and some other warm regions.

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.