Natural rubber primarily comes from the latex sap of the rubber tree, scientifically known as Hevea brasiliensis. This tree is native to the Amazon rainforest in South America but is now widely cultivated in tropical regions, especially in Southeast Asia, including countries like Thailand, Malaysia, Indonesia, and Cambodia, which produce over 90% of the world's natural rubber supply

. The latex is harvested through a process called tapping, where incisions are made in the bark of the tree to collect the milky sap. This sap is then processed by coagulation and further treatment to produce usable rubber

. Historically, natural rubber was first used by indigenous peoples in Mesoamerica, such as the Olmecs and Maya, who extracted latex from native rubber trees like Castilla elastica. European explorers later encountered rubber in the Americas, and commercial cultivation expanded globally after the smuggling of rubber seeds to Asia in the late 19th century

. In summary, rubber comes from the latex of the Hevea brasiliensis tree, originally from the Amazon but now mainly produced in Southeast Asia through plantation farming.