你记错了或者你最初看的就是错的，美国禁止花椒是担心传染植物疾病

From 1968 to 2005,^[16] the United States Food and Drug Administration banned the importation of Sichuan peppercorns because they were found to be capable of carrying citrus canker (as the tree is in the same family, Rutaceae, as the genus Citrus). This bacterial disease, which is very difficult to control, could potentially harm the foliage and fruit of citrus crops in the U.S. It was never an issue of harm in human consumption. The import ban was only loosely enforced until 2002.^[17] In 2005, the USDA and FDA lifted the ban, provided the peppercorns are heated for ten minutes to around 70 °C (158 °F) to kill any canker bacteria before import.