The purpose of this retrospective study was to report the peritoneal fluid lactate (PFL) levels in horses diagnosed with nonstrangulating small intestinal (NSSI) lesions and to compare those values to horses diagnosed with strangulating small intestinal (SSI) lesions. Medical records between 2005 and 2016 were reviewed. Subject details, presenting clinical findings, and disease category (strangulating/NSSI lesion) were obtained. Comparison of SSI lesions to NSSI lesions revealed no significant difference in PFL values. However, horses with SSI lesions had significantly higher peritoneal fluid lactate:blood lactate ratios and were more likely to have serosanguinous peritoneal fluid color than those with NSSI lesions.