Zanthoxylum rhetsa, commonly known as Indian prickly ash,[3] is a species of flowering plant in the family Rutaceae and occurs from India east to the Philippines and south to northern Australia.

It is a deciduous shrub or tree with cone-shaped spines on the stems, pinnate leaves with between nine and twenty-three leaflets, panicles of white or yellowish, male and female flowers, followed by spherical red, brown or black follicles.

[8][9] Z. schinifolium Z. avicennae Z. rhetsum Z. myriacanthum Z. ailanthoides Z. kauaense Z. hawaiiense Z. dipetalum Z. dissitum Z. scandens Z. echinocarpum Z. oxyphyllum all other Zanthoxylum species Zanthoxylum rhetsa grows in rainforest and coastal thickets from sea level to an altitude of 200 m (660 ft), and is found in India, east to the Philippines and south to northern Australia.

[4][5][11][12] The people of Goa, the Konkan and Kanara coasts, and Coorg use the woody pericarp of the tiny fruits as a spice, particularly with seafood dishes.

In the Northwest region of Vietnam, the spice is known as "mắc khén" and is used particularly by people of the Muong ethnic minority on grilled meats and in dipping sauces.