an active ingredient in many antacid preparations that causes small mucus-entrapped air bubbles in the intestines to coalesce into larger bubbles that are more easily passed.
Main Entry: si·meth·i·cone Pronunciation: si-'meth-i-"kOn, sI- Function: noun : a mixture of dimethylpolysiloxanes and silica in liquidor tablet form that is used as an antiflatulent —see MYLICON