Pirayan, sihora in Hindi, is the Siamese rough bush or sandpaper tree, a small, milky-sapped tree whose leaves are so rough that they are used to scour utensils and polish wood. Its twigs are chewed as datun, a natural toothbrush, in villages across India. In Thailand its bark was beaten into khoi paper for traditional folding manuscripts. It is not Salvadora persica, the arak tree used for miswak.
- Botanical name
- Streblus asper Lour.
- Family
- Moraceae
- Tamil
- Pirayan
- Hindi
- Sihora
- Parts used
- Twig, Leaf, Bark in lists
- Habit
- Sandpaper-leaf tree; its twigs are used as chew sticks
- Last updated
- 2026-10-27
How to recognise Pirayan
It is a shrub or small tree, often crooked, with grey bark and milky latex.
The leaves are small, stiff and oval, with a very rough, sandpaper-like surface.
Male flowers form small round heads; female flowers sit singly on separate plants.
The fruit is a small, round, yellow berry wrapped in fleshy sepals.
Salvadora has smooth, fleshy, pale green leaves and a mustard-like smell.
Traditional use of Pirayan
Household
Fresh twigs are chewed into a brush and used to clean teeth as datun.
Indian village practice
Household
The rough leaves are used to scrub pots and to smooth wood and ivory.
South and South-east Asian household practice
Craft
In Thailand bark fibre was made into khoi paper for samut khoi manuscripts.
Thai craft history
Modern notes on Pirayan
Laboratory studies report activity of twig extracts against bacteria involved in tooth decay.
Small studies of chewing sticks suggest they can clean teeth, but they do not replace a toothbrush and fluoride toothpaste.
The leaves are rough because of hard, mineral-rich hairs.
Pirayan safety
Use only fresh, clean twigs from trees away from roads, and do not swallow the latex. Children should use a regular toothbrush.
Ecology and sourcing
It grows from India and Sri Lanka to South-east Asia and southern China.
Birds eat the yellow fruits.
It tolerates poor soil and is common in village scrub.
Related plants
Also in Moraceae
Questions about Pirayan
Why is Pirayan called sandpaper tree?
Its leaves are rough enough to polish wood.
Is Pirayan used for brushing teeth?
Yes, as a datun chew stick.
Is Pirayan the same as miswak?
No. Miswak comes from Salvadora persica.
What is khoi paper?
Thai paper made from its bark.
Does Pirayan have latex?
Yes, milky latex.
Sources
- Streblus asper Lour. — Plants of the World Online, Kew (search) (accessed 2026)
- Wikidata item Q23370 (Streblus asper)
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.