PDA [Digestive] supplements the body's digestive secretions with hydrochloric acid (HCl). The stomach manufactures hydrochloric acid to break down proteins. But, as people age, they may produce less HCl, which can affect the amount of protein they can break down and ultimately absorb. Inefficient protein digestion can affect the viability of the intestinal flora that feast on these compounds. Each capsule of PDA provides 325 mg of betaine HCl, supplying diluted hydrochloric acid and 20 mg of pepsin, a natural protein-digesting enzyme. Take 1-4 capsules with a meal three times daily.