Sichuan peppercorn is a spice produced from the husks of seeds of two species of the prickly ash shrub (Zanthoxylum), which is in the rue or citrus family. The pinkish-red husks around the seeds are used for the Sichuan peppercorn spice, while the inner black seed is discarded as it is too gritty and would be sand-like when eaten. On the tongue, the first taste is bitter, then numbing heat, followed by citrus oils, mostly carvone and limonene.