马尿酸（Hippuric acid），学名苯甲酰胺乙酸，分子式C₉H₉NO₃，结构简式C₆H₅CONHCH₂CO₂H，该词起源于希腊语的Hippos（horse）和ouron（urine）。它是一种在马和草食性动物尿液中发现的有机酸。苯甲酰胺乙酸晶体易溶于热水，在187℃左右熔化，大约于240℃分解。许多种的芳香化合物（比如苯甲酸和甲苯）摄入体内后，都会通过和氨基酸（如甘氨酸）反应转化为苯甲酰胺乙酸，因此，体内马尿酸浓度过高可能是由甲苯中毒导致的。由于引起苯甲酰胺乙酸中毒的因素还有很多，因此科学家对两者之间的联系仍存怀疑。。

Hippuric acid (Gr. hippos, horse, ouron, urine) is a carboxylic acid found in the urine of horses and other herbivores. Hippuric acid crystallizes in rhombic prisms which are readily soluble in hot water, melt at 187 °C, and decompose at about 240 °C. High concentrations of hippuric acid may also indicate a toluene intoxication; however, scientists have called this correlation into question because there are other variables that influence levels of hippuric acid. When many aromatic compounds such as benzoic acid and toluene are taken internally, they are converted to hippuric acid by reaction with the amino acid, glycine.