An unarmed shrub or tree mostly 1.5 to 5 m tall but occasionally reaching 12 m. The trunk is 50 to 300 mm thick with a corky, pale brown bark with longitudinal fissures. Twigs have prominent leaf scars that form transverse ridges.

The leaves are leathery, opposite and dark glossy green above and paler beneath. Leaf dimensions vary from 90 to 200 mm by 50 to 70 mm, and are generally 2 to 4 times as long as wide. The petioles are 10 to 25 mm long. The raised midrib and lateral nerves are particularly visible on the underside of the leaf.

Each inflorescence consists of many white, fragrant flowers and is borne on a 30 to 50 mm-long peduncle. Each flower is up to 15 mm wide and is borne on a 4 to 7 mm-long pedicel.

The fruit are in pairs, subglobose, with a green skin that is covered in pale warts. Each fruit is 60 to 70 mm long by 40 to 50 mm wide, with two lateral ridges and one dorsal ridge. The fruit are leathery to woody, with a wall that is 5 to 15 mm thick. When mature, they split open along one side, often while still on the tree, displaying the yellowish pulp inside. Each fruit with its green, warty skin resembles a toad, giving rise to the common name toad tree. Embedded in the yellow pulp are numerous dark brown seeds 14 to 17 mm long by 7 to 9 mm wide. 

All parts of the plant are hairless and have a milky sap.