BACKGROUND: Despite Cryptostegia grandiflora Roxb. ex R. Br. (Apocynaceae) leaves are widely used in folk Caribbean Colombian medicine for their anti-inflammatory effects, there are no studies that support this traditional use. Therefore, this work aimed to evaluate the effect of the total extract and primary fractions obtained from Cryptostegia grandiflora leaves, using in vivo and in vitromodels of inflammation, and further get new insights on the mechanisms involved in this activity. RESULTS: Ethanolic extract of Cryptostegia grandiflora leaves, and its corresponding ether and dichloromethane fractions, significantly reduced inflammation and myeloperoxidase activity (MPO) in ear tissue of mice treated with 12-O-tetradecanoyl-phorbol-13-acetate (TPA). Histological analysis revealed a reduction of edema and leukocyte infiltration. Complementarily, we demonstrated that extract and fractions reduced nitric oxide (NO ) and prostaglandin E2 (PGE2) production in LPS-stimulated RAW 264.7 macrophages, as well as scavenging activity on DPPH and ABTS radicals. CONCLUSIONS: Our results demonstrated for the first time the anti-inflammatory activity of Cryptostegia grandiflora leaves, supporting its traditional use. This activity was related to inhibition of MPO activity, and PGE2 and NO production. These mechanisms and its antioxidant activity could contribute, at least in part, to the anti-inflammatory effect showed by this plant.