In general Catappa Leaves are quite big in size, there are tiny ones from 5 centimetres (2 Inches) to as big as 30 centimetres (12 Inches) long and 10 to 15 centimetres broad (4-5.5 inches broad). They are thick and leathery with an ovoid shape and sport a glossy dark green colour. Before shedding its leaves to survive the dry season, the Terminalia Catappa tree will retract the valuable green pigmentation, leaving the leaves pinkish-reddish or yellow-brown.

Catappa leaves contain several different flavonoids, including kaempferol and quercetin. It is also rich in various tannins; astringent, bitter plant polyphenols that either bind and precipitate or shrink proteins.The compounds found in the leaves have made them an integral part of traditional medicine within their native range, and local communities in the Americas have also adopted them into their collections of home remedies.

Aquarists who keep fish native to soft, acidic and tannin rich waters - such as the Betta fish - commonly use Catappa leaves to mimic the natural conditions of their species in aquaria. Adding Catappa leaves to a tank can for instance help trigger spawning since compounds released by the leaves will alter the chemistry of the water, making the aquarium more similar to the habitat from which the fish hails.