2,4,5-Trihydroxybenzaldehyde (2,4,5-THBA) is a tri-substituted benzaldehyde that can be prepared from sesamol. Its free radical-quenching ability, antioxidant bioactivity and cytotoxicity have been assessed. 2,4,5-THBA has been identified as one of the components in the ethyl acetate extract of Beta vulgaris var. cicla seeds. The freezing point, boiling point, density and refractive index of 2,4,5-THBA are 499. 65K, 510. 61K, 1. 3725g/cm3 and 1. 6400, respectively.