This study evaluated the chemical composition, antioxidant and anticholinesterase activities, and the toxicity of hydroethanolic extracts of the Parkia platycephala Benth. Hot extraction with 70% hydroethanolic solution was used to obtain crude extracts of the leaf (LE), bark (BE), flower (FE), and seed (SE). Separation and identification of the compounds were performed by liquid chromatography with diode array detection and gas chromatography coupled with mass spectrometry. Antioxidant and anticholinesterase activities were performed by the 2,2-diphenyl-1-picrylhydrazyl (DPPH•) and Ellman methods, respectively, and the preliminary toxicity by the method with Artemia salina. Chromatography analysis indicated naringin, kaempferol, stigmasterol, and β-sitosterol in all extracts. Gallic acid is prominent in the LE and FE, while ferulic acid is abundant in the BE and lupeol and lupeol acetate are prominent in the SE. The BE antioxidant activity (lethal concentration of 50% (IC50) = 14.72 ± 0.13 µg mL-1) is equivalent to the standard rutin (IC50 = 15.85 ± 0.08 µg mL-1). The SE had the best acetylcholinesterase inhibition potential (IC50 = 5.73 ± 0.68 µg mL-1). Aside from the SE, which is not toxic, the other extracts had low (LE, FE) and moderate (BE) toxicity. The extracts of P. platycephala have potential antioxidant and therapeutic uses, especially against Alzheimer’s disease.