Aegle marmelos is a deciduous shrub or small to medium-sized tree, up to 13 metres (43 feet) tall with slender drooping branches and rather open, irregular crown.

[10] The bark is pale brown or grayish, smooth or finely fissured and flaking, armed with long straight spines, 1.2–2.5 centimetres (1⁄2–1 inch) singly or in pairs, often with slimy sap oozing out from cut parts.

[11] The flowers are 1.5 to 2 cm, pale green or yellowish, sweetly scented, bisexual, in short drooping unbranched clusters at the end of twigs and leaf axils.

The bael tree contains furocoumarins, including xanthotoxol and the methyl ester of alloimperatorin, as well as flavonoids, rutin and marmesin; a number of essential oils; and, among its alkaloids, á-fargarine(=allocryptopine), O-isopentenylhalfordinol, O-methylhafordinol.

[9] Aegle marmelos is native across the Indian subcontinent and Southeast Asia, and is cultivated throughout Sri Lanka, Tamilnadu, Thailand, and Malesia.

[citation needed] Aegeline is a known constituent of the bael leaf and consumed as a dietary supplement with the intent to produce weight loss.

[15][16] In 2013, the U.S. Food and Drug Administration (FDA), Centers for Disease Control and Prevention (CDC), the Department of Defense Armed Forces Health Surveillance Center, and Hawaii state and local health officials identified an outbreak of 97 persons with acute non-viral hepatitis that first emerged in Hawaii.

Seventy-two of these persons had reported using the dietary supplement OxyElite Pro, containing aegeline, which was manufactured by the Dallas company, USPlabs.

[15][19] All of these patients had been using the reformulated OxyElite Pro, which they had purchased from different sources, and which had different lot numbers and expiration dates, at doses within the manufacturer's recommendation.

[15] Rich in vitamin C,[12] the fruits can be eaten either fresh from trees or after being dried[21] and produced into candy, toffee, pulp powder or nectar.

Bela Pana made in Odisha has fresh cheese, milk, water, fruit pulp, sugar, crushed black pepper, and ice.

Bæl pana, a drink made of the pulp with water, sugar, and citron juice, is mixed, left to stand a few hours, strained, and put on ice.

[24][25] Earliest evidence of the religious importance of bael appears in the Sri Sukta of the Rigveda, which reveres this plant as the residence of goddess Lakshmi, the deity of wealth and prosperity.

[4][29] In the traditional practice of the Hindu and Buddhist religions by people of the Newar culture of Nepal, the bael tree is part of a fertility ritual for girls known as the Bel Bibaaha.