Chili peppers, which are now a defining feature of Chengdu's fiery Sichuan cuisine, are not native to China but originated in Central and South America. They were introduced to the Chinese mainland in the late 16th century via European explorers and traders, likely brought by Portuguese or Spanish navigators from the Americas to coastal trading hubs. While initially used as ornamental plants in coastal regions like Zhejiang, the peppers gradually spread inland to southwestern China, including Sichuan and Guizhou, by the late 17th and 18th centuries. Before the arrival of the chili pepper, the "spice" in Chengdu's food was derived from indigenous ingredients such as the numbing Sichuan peppercorn (huajiao), ginger, mustard, and a now-rarely-used spicy seed called zhu yu (Evodia). The chili pepper eventually reached Sichuan through overland trade routes from Southeast Asia or India and was widely adopted by the local population because it was affordable, easy to cultivate in the region's humid basin climate, and effectively complemented the existing numbing flavors to create the modern "ma la" (numbing and hot) profile.