The flavonoids kaempherol and epicatechin, and a proanthocyanidin fraction were isolated from the seed of allspice (Pimenta dioica). Their structures were determined by chemical and spectral analyses. Antioxidant activities of kaempherol, epicatechin and the proanthocyanidin fraction were tested using the reaction with the stable radical diphenyl-p-picrylhydrazyl (DPPH) and exhibited IC₅₀ values of 7.83, 4.27 and 2.92 g/mL, respectively. These results demonstrate that allspice proanthocyanidins and flavonoids might act as effective antioxidants.