In this investigation, cactus extract is used as a natural organic admixture in an ordinary portland cement. It is seen that cactus extract improves the plasticity of the mortar, workability and compressive strength of the concrete. Setting time of cement has been delayed due to moisture holding capacity of carbohydrates present in the cactus. FT-IR for organic analysis and SEM for microstructure was studied. Organic test on cactus was done to determine the presence of fat, protein and carbohydrates. Scattered formation of calcite from SEM image indicates the improvement in compressive strength of the concrete.