E-Z-Paste® Barium Sulfate Esophageal Cream (60% w/w) is a barium sulfate cream for oral administration. Each 100 g contains 60 g barium sulfate. Barium sulfate, due to its high molecular density is opaque to x-rays and, therefore, acts as a positive contrast and agent for radiographic studies. The active ingredient is barium sulfate and its structural formula is BaSO4. Barium sulfate occurs as a fine, white, odorless, tasteless, bulky powder which is free from grittiness. Its aqueous suspensions are neutral to litmus. It is practically insoluble in water, solutions of acids and alkalies, and organic solvents.