Diseases of the colon are treated by oral ingestion of a unit dosage form containing a mast cell stabilizer as an active agent. The dosage form is targeted for delivery of the active agent to the colon or when in an immediate release formulation, such as a fast-dissolving tablet, powder or effervescent, the targeted release is upon ingestion. The dosage form comprise at least one mast cell stabilizer such as but not limited to ketotifen, nedocromil sodium, cromolyn sodium, and antihistamines which have mast cell stabilizing properties such as, but not limited, to azestastine hydrochloride and olopatadine hydrochloride, which remains intact until the dosage form reaches the colon or until ingestion.