Kokoona zeylanica (Kokun) ෴ කොකුන්

Kokoona zeylanica, known in Sinhala as කොකුන් (Kokun) is a species of plant in the family Celastraceae. It is not to be confused with the similar sounding word කොකුම් which stands for the Kokum plant. The genus was formerly classified in the family Hippocrateaceae. It is endemic to Sri Lanka. It is extant at Adam's Peak and at Kanneliya.

The kokun is a large tree with a rough grey bark 20-35 m high, Leaves 3.4-8.4 x 2.4-4.6 cm; petioles 8-10 mm long. Flowers 6-8 mm diameter, dull yellowish-brown. Capsules 10.2 x 2.0 cm, black. Seeds light brown, 6.5-8.0 cm long.

The kokun is regarded as a medicinal plant traditionally used in a number of conditions. The seed oil from this plant is effective as a leech repellent.

Kokoona zeylanica is part of the catalog of ayurvedic medicinal plants of Sri Lanka.