Due to the ethnopharmacological use of Campsiandra laurifolia (Fabaceae), popularly known as Acapurana, to treat wounds and ulcers, associated with the lack of alternative treatments for intestinal inflammations such as ulcerative colitis (UC), the present work sought to characterize its phytochemical and antioxidant activities, and to evaluate remedial action in experimental colitis with acetic acid. Phytochemical analyzes were performed through qualitative and quantitative colorimetric tests of the main secondary metabolites. In the colitis model, 24 male Wistar rats aged ± 60 days old were used, divided into 4 groups: Control (CO) control + aqueous extract of C. laurifolia 50 mg/kg (CO + A50); Colitis (CL); and Colitis + aqueous extract of C. laurifolia 50 mg/kg (CL + A50). Measurement of sphincter anal pressure and histological tests of the large intestine, lipoperoxidation (LPO), enzyme activity of superoxide dismutase (SOD), and levels of glutathione (GSH) were performed. For statistical analysis, the oxidative stress (OS) results were expressed as means ± standard error, adopting a significance level of p < 0.05. The screening indicated the presence of flavonoids, saponins and tannins in the extract, with high levels of phenolic compounds and tannins, and was related to high antioxidant capacity. In the histological analysis, the CL group presented loss of the crypts, edema and inflammatory infiltrate. The use of C. laurifolia extract restructured the crypts, decreased edema and increased sphincter anal pressure, with a decrease in LPO, SOD, and an increase in GSH. It is suggested that the use of C. laurifolia extract reduces OS due to its antioxidant power conferred by the phenolic compounds present in the extract.