Schinus terebinthifolia Raddi (Anacardiaceae), known as Brazilian pepper tree, stands out as a medicinal plant widely used in traditional medicine. The leaves are popularly used as anti-inflammatory agent and to relieve inflammatory conditions such as bronchitis, ulcers, and wounds, for example. The present study evaluated the acute toxicity, genotoxicity, and anti-inflammatory activity of S. terebinthifolia leaf lectin (SteLL) in mice (Mus musculus). In the acute toxicity assay, the animals were treated intraperitoneally (i.p.) or orally (per os) with a single dose of 100 mg/kg. Genotoxicity was assessed by the comet and micronucleus assays. Carrageenan-induced peritonitis and paw edema models were used to evaluate the anti-inflammatory effects of SteLL (1, 5 and 10 mg/kg, i.p.). No animal died and no signs of intoxication or histopathological damage were observed in the acute toxicity assay. Genotoxic effect was not detected. In peritonitis assay, SteLL reduced in 56–69% leukocyte migration to the peritoneal cavity; neutrophil count decreased by 25–32%, while mononuclear cell count increased by 67–74%. SteLL promoted a notable reduction of paw edema after 4 h (61.1–63.4%). Morphometric analysis showed that SteLL also decreased the thickness of epidermal edema (30.2–40.7%). Furthermore, SteLL decreased MPO activity, plasma leakage, NO release, and modulated cytokines in both peritoneal fluid and paw homogenate. SteLL did not induce acute toxicity or genotoxicity in mice and stands out as a promising candidate in the development of new phytopharmaceuticals with anti-inflammatory action. Display omitted