Diluents act as fillers in pharmaceutical tablets to increase weight and improve content uniformity. Natural diluents include starches, hydrolyzed starches, and partially pregelatinized starches. Common diluents include anhydrous lactose, lactose monohydrate, and sugar alcohols such as sorbitol, xylitol and mannitol. Diluents provide better tablet properties such as improved cohesion or to promote flow. Mannitol is one of the costliest dilents, however, it is still often used due to the sensation it provides when it is used in chewable tablets. Diluents must be non-toxic, commercially available in acceptable grade, physiologically inert, and physically and chemmically stable by themselves as well as in combination with active pharmaceutical ingredients (APIs).