The Sitaphal, Custard Apple, tree or Annonaceae is a medicinal plant of India which is also popular as Sweet Sop tree. It is cultivated throughout the tropics and warmer subtropics for its edible fruit, and has become naturalized throughout India to an altitude of 900 m. The botanical name of Custard Apple tree is Annona squamosa L and bears numerous common names. The major ones are Ata and Seetaphal in Bengali, and gandhagataram, gandagatra, krishnabija, seetaaphalam and sitaphala in Sanskrit.

It is a small tree with a height of 3-8 meter. The Custard Apple tree has leafy branches with thin, dark brown to grayish bark. Leaves of this tree are oblong-lanceolate or elliptic, which are 5-15 cm long and 2-5.5 cm wide. The flowers are fragrant, varies from creamy-yellow to greenish colour. The fruits of Custard Apple tree are ovoid in shape that measures 5-12 cm in diameter. On maturing, these fruits turn yellowish-green colour. The ripen fruits are marked with prominent scales and filled with an edible, juicy, pulp surrounding to the smooth, shining, brownish-black seeds.

These Custard Apple trees are used in different medicinal purposes throughout the country. The ripe fruit of this tree possesses astringent, cooling, febrifugal and pectoral properties. It works as a tonic for the blood and improve muscular strength. It is excellent for the digestive system and is prescribed for vomiting, diarrhoea, dysentery and vertigo.

The fruits of the Custard Apple tree are of great medicinal value. The dried, powdered, unripe fruits are considered effective in healing ulcers, and are used as an insecticide, particularly for lice. Both the ripe pulp and crushed leaves are mixed with salt and applied as a poultice to hasten suppuration of boils and to relieve pains and swellings.

The leaves of these Custard Apple trees are used to prevent bedbugs and maggots, and are also used to extract guinea worms. These leaves possess stimulant, anthelmintic and insecticidal properties. The tea made from these leaves is used to recover from fever. Fresh leaf-juice is applied to the nostrils in cases of hysteria and fainting. The leaves and fruits of Custard Apple trees are used for the treatment of tumours and the leaf extracts have anti-cancer properties.

Another major part of this plant is the root which has an important medicinal property. These roots are reported to be diuretic and a strong purgative which are used for the disease of acute dysentery. They are also used for the treatment of depression, spinal diseases, asthma and fever. The seeds are used as a contraceptive and as an abortifacient.

The seeds of the Custard Apple are known for their insecticidal and pesticide properties. These are strong irritants to the conjunctiva and have been reported to cause blindness.