Espumisan contains the active substance simethicone, which is an agent used in gastrointestinal disorders, reducing the foaming of the gastrointestinal contents and used as an aid in diagnostic tests. The active substance of the drug, simethicone, causes the rupture of gas bubbles contained in the food masses and in the gastrointestinal mucus. As a result, the gases released in this way can be absorbed through the intestinal wall or removed from the gastrointestinal tract as a result of peristaltic movements of the intestines.