2,3-二巯基丁二酸（Dimercaptosuccinic acid、英文缩写为：DMSA），别名2,3-二巯基琥珀酸，一般简称二巯基丁二酸，是一种有机硫化合物，常温下为白色结晶状粉末。因分子内含有两个巯基，所以它带有巯基化合物特有的臭味。二巯基丁二酸和它的钠盐都可以作为解毒剂通过口服或注射治疗重金属中毒。 二巯基丁二酸有两种非对映异构体，一种是内消旋体，另一种是外消旋体。内消旋体可作为螯合剂使用，常用其钠盐。

Dimercaptosuccinic acid (DMSA), also called succimer, is the organosulfur compound with the formula HO₂CCH(SH)CH(SH)CO₂H. This colorless solid contains two carboxylic acid and two thiol groups, the latter being responsible for its mildly unpleasant odour. It occurs in two diastereomers, meso and the chiral dl forms. The meso isomer is used as a chelating agent for treatment of heavy metal toxicity, and is a water-soluble and non-toxic substance. When radiolabeled with technetium-99m, it helps in diagnostic testing of renal function.