Tropical Ingredients

Langsat

Lansium domesticum

Pleasantly acidic when fully ripe, with a sharper, more sour edge.

5 min read·Updated September 23, 2026
Growing regions: Southeast Asia
Other names: Langsat (Malay, Indonesian); Duku (Malay, Indonesian); Lanzones, lansones (Filipino/Tagalog); Longkong (Thai); Bòn bon (Vietnamese)
Family Meliaceae Best for Preserves

Description

Langsat is the fruit of a small to medium evergreen tree in the Meliaceae family, native to western Southeast Asia. The fruit grows in dangling clusters along the branches, each one a small, oval-to-round berry roughly two to four centimetres across, with a pale yellowish to light-brown skin that is often slightly velvety.

Inside, the skin parts to reveal translucent, white, juicy flesh divided into segments — a structure it shares with its relatives in the same tree family. The flavour is sweet-tart and lightly fragrant: pleasantly acidic when fully ripe, with the sharper, more sour edge that distinguishes langsat from its sweeter kin. Most segments hold a seed, and the peel, when broken, exudes a sticky white latex that can cling to the fingers.

One Species, Several Market Names

Langsat is not a single fixed fruit type but one form of Lansium domesticum, and the tree carries several market types under different names that are all the same species, not separate fruits:

  • Langsat — smaller fruit, thinner skin, more sour, and heavy with milky latex.
  • Duku — larger, rounder fruit, thicker skin, sweeter and generally free of latex.
  • Duku-langsat — an intermediate form with medium fruit and a balance of the two.
  • Longkong (dokong) — thick-skinned, sweet and nearly seedless, widely grown in southern Thailand.

Because the names are used loosely and the trees look nearly identical, telling them apart reliably often comes down to the fruit. Check the Latin name when it matters; "langsat" and "duku" are names of types within one species, not boundary lines between species.

Origin & History

Lansium domesticum is native to a region stretching from Peninsular Thailand through the western and central parts of Malesia — including Peninsular Malaysia, Sumatra, Java, Borneo, Sulawesi and the Philippines — and has been cultivated and traded across Southeast Asia for centuries. Thailand, Malaysia, Indonesia and the Philippines are its main producers. It thrives in the humid lowland tropics, fruiting best near sea level and struggling with frost.

The tree is primarily a garden and market fruit, rarely travelling far from the region where it is grown, which keeps it a seasonal, locally enjoyed treat rather than a broad export crop.

Uses

Culinary

  • Fresh: Peeled and eaten out of hand, segment by segment — the usual and best way
  • Preserved: Seedless fruit is sometimes bottled in syrup

Traditional Medicinal Uses

Various parts of the tree — peel, seeds and bark — appear in Southeast Asian folk medicine, and the dried peels were traditionally burnt as a mosquito repellent. These are traditional uses; they are not a basis for treating illness, and the fruit should not be presented as medicinal.

Other Uses

The dense wood of the tree is durable and has been put to use for posts and tool handles.

Nutritional Benefits

Langsat is mostly water and provides carbohydrate along with small amounts of minerals, notably potassium, and a little vitamin C. Because the fruit varies between langsat and duku types, and precise figures differ by source and season, exact numbers are not a reliable guide; it is best treated as a light, refreshing fruit rather than a nutrient-dense one.

What Not to Eat

Eat only the translucent flesh. The seeds are bitter and are not eaten, and the latex-bearing skin is discarded. Take the usual care to eat only the ripe, fresh flesh and not the pit.

How to Prepare

  1. Select: Choose fruit that is full and firm, with intact skin and no mould or cracks. Buy mature, straw-yellow fruit; do not rely on green-picked fruit becoming sweeter after purchase.
  2. Open: Pinch or press the skin near the stem end to split it, then peel it back to reveal the segmented flesh.
  3. Separate: Pull off the segments and work around any seeds inside; discard the seeds.
  4. Eat fresh: Langsat is best eaten soon after picking or purchase and does not store for long.
Tips: The latex from the peel can stick to your hands — rinse or wipe them after peeling rather than pulling the fruit apart messily. Sourer langsat suits a pinch of salt or a little chilli-salt for balance. Check each segment for a seed before biting down; the seeds are hard and bitter.

Recipes

As Jungle Kitchen develops recipes featuring langsat, those will be linked here.

Suggested applications: chilled langsat as a snack, a langsat and citrus fruit salad, seedless langsat bottled in syrup.

Varieties

Langsat is generally understood through those market types — langsat, duku, duku-langsat and longkong — rather than through separate named species. Botanically, two varieties are recognised within Lansium domesticum: var. pubescens, the older, more latex-rich wild langsat, and var. domesticum, the duku form. Commercial fruits sold under local names (such as the Philippine 'Paete' lanzones) are selections within these types rather than distinct species.

Fun Facts

  • The genus name Lansium belongs to the Meliaceae family, which also includes the mahogany and neem trees.
  • Market names overlap, and fruit size, skin thickness and latex help explain the distinction between duku and langsat types.
  • The peel's sticky latex is a telling trait: langsat type has it in abundance, duku barely any.
  • Longkong, the sweet, nearly seedless type, is a relatively recent star of the Thai fruit trade.