The papaya (from Carib via Spanish), papaw, or pawpaw is the fruit of the plant Carica papaya, the sole species in the genus Carica of the plant family Caricaceae. It is native to the tropics of the Americas, and was first cultivated in Mexico several centuries before the emergence of the Mesoamerican classical civilizations. The papaya is a large tree-like plant, with a single stem growing from 5 to 10 metres (16 to 33 ft) tall, with spirally arranged leaves confined to the top of the trunk. The lower trunk is conspicuously scarred where leaves and fruit were borne. The leaves are large, 50–70 centimetres (20–28 in) diameter, deeply palmately lobed with 7 lobes. The tree is usually unbranched, unless lopped. The flowers are similar in shape to the flowers of the Plumeria, but are much smaller and wax-like. They appear on the axils of the leaves, maturing into the large 15–45 centimetres (5.9–18 in) long, 10–30 centimetres (3.9–12 in) diameter fruit. The fruit is ripe when it feels soft (as soft as a ripe avocado or a bit softer) and its skin has attained an amber to orange hue.
Papayas can be used as a food, a cooking aid, and in traditional medicine. The stem and bark may be used in rope production.Papaya fruit is a rich source of nutrients such as provitamin A carotenoids, vitamin C, B vitamins, dietary minerals and dietary fibre. Papaya skin, pulp and seeds also contain a variety of phytochemicals, including polyphenols. The ripe fruit of the papaya is usually eaten raw, with or without skin or seeds. The unripe green fruit can be eaten cooked, usually in curries, salads, and stews. Green papaya is used in Southeast Asian cooking, both raw and cooked. In Thai cuisine, papaya is used to make som tam and kaeng som when still not fully ripe. In Indonesian cuisine, the unripe green fruits and young leaves are boiled for use as part of lalab salad, while the flower buds are sautéed and stir fried with chillies and green tomatoes as Minahasan papaya flower vegetable dish. Papayas have a relatively high amount of pectin, which can be used to make jellies. The smell of ripe, fresh papaya flesh can strike some people as unpleasant. The black seeds of the papaya are edible and have a sharp, spicy taste. They are sometimes ground and used as a substitute for black pepper. In some parts of Asia, the young leaves of the papaya are steamed and eaten like spinach. In some parts of the world, papaya leaves are made into tea as a treatment for malaria. Anti-malarial and anti-plasmodial activity has been noted in some preparations of the plant, but the mechanism is not understood and no treatment method based on these results has been scientifically proven.
Both green papaya fruit and the tree's latex are rich in papain, a protease used for tenderizing meat and other proteins. Its ability to break down tough meat fibers was used for thousands of years by indigenous Americans. It is now included as a component in powdered meat tenderizers.
Papaya is frequently used as a hair conditioner, but should be used in small amounts. Papaya releases a latex fluid when not quite ripe, which can cause irritation and provoke allergic reaction in some people. The papaya fruit, seeds, latex, and leaves also contains carpaine, an anthelmintic alkaloid (a drug that removes parasitic worms from the body), which can be dangerous in high doses. It is speculated that the latex concentration of unripe papayas may cause uterine contractions, which may lead to a miscarriage. Papaya seed extracts in large doses have a contraceptive effect on rats and monkeys, but in small doses have no effect on the unborn animals. Excessive consumption of papaya can cause carotenemia, the yellowing of soles and palms, which is otherwise harmless. However, a very large dose would need to be consumed; papaya contains about 6% of the level of beta carotene found in carrots (the most common cause of carotenemia).