Garcinia atroviridis is known as Asam Gelugur or Asam Keping in Malay. The species belongs to the Guttiferae, the mangosteen family. It is a large rainforest tree, native to Malaysia, India, Myanmar and Indo-China. In Peninsular Malaysia, this species grows wild in lowland and hill forest to 600 m altitude but is also widely cultivated for its economic and medicinal value.

The Gelugor district in Penang, now a satellite town of George Town, is named after the tree, also known as "Gu-Lu-Gok" by the local Hokkien.

Garcinia atroviridis grows to 25 m tall. It has a trunk fluted at the base with dull grey, cracked and fissured bark and drooping branches. The tree produces a little transparent or yellow sap from the inner bark. Leaves on young shoots are reddish, and then become dark glossy green when mature. The laminas are narrowly oblong, pointed at the tip and abruptly tapered at the base. This species is a dioecious tree with unisexual flowers. The female flowers are borne solitary and are reddish, large and sometimes faintly fragrant. In contrast, male flowers are borne in terminal clusters. The male flowers are uncommon with most trees being female because female trees are selected for planting in the villages due to their use. The fruits are juicy, round, about 7 to 10 cm in diameter and fluted with 12 to 16 ribs and grooves. It turns orange-yellow when ripe with the large brownish disc-like stigma persistent at the tip. The seeds are a bright orange colour.

Asam Gelugur has been used for a long time. It was said that a decoction of the leaves has traditionally been used for the treatment of earache. The fruit is cut into slices and sun-dried and sold commercially in markets and sundry shops, where it is known as Asam Keping. It is extremely sour and is used in cooking curries, stews and soups or for dressing fish. The fruit is also said to have medicinal value. The fruits contain ascorbic acid, which is antibacterial, and citric acid that can reduce obesity and lower cholesterol and excess fat. Malay women used to drink a decoction of Asam Gelugur to deflate the stomach after childbirth. Furthermore, Chinese believe chewing the fruits can eliminate bad breath.