苏木（学名：Caesalpinia sappan）为豆科云实属的植物。又名苏方、苏方木、苏枋木、苏枋、红紫、赤木。多分布在东南亚和中国南部一带。

常绿小乔木，有少数小刺，叶片为二回羽状复叶。每年6月至9月开黄色花，花为5瓣、圆锥花序。红棕色木质荚果，不开裂。

Caesalpinia sappan is a species of flowering tree in the legume family, Fabaceae, that is native to Southeast Asia and the Malay archipelago. Common names include Sappanwood, Sapanwood, Patanga-Chekke Sappanga (Kannada), Pathimukham (Malayalam), and Suō (Japanese). Sappanwood belongs to the same genus as Brazilwood (C. echinata), and was originally called "brezel wood" in Europe.