The orange tree, originally from Southeast Asia, later spread to India and Persia before expanding throughout the Mediterranean basin, where it was first cultivated during the 10th century. It was subsequently grown in California and South America. Sweet orange oil is obtained by extracting the zest of the fruit. The fruit of the orange tree was an integral part of ancient Chinese medicine, particularly for stimulating digestion and soothing spasms. In 18th-century Europe, the fruit of the orange tree was used to treat nervous and cardiac disorders, as well as colic and asthma.