An antifoaming agent is a chemical additive that inhibits the formation of foam. When used as an oil additive to the base stock of oil, antifoam agents prevent the oil from foaming and frothing during high speed mechanical agitation. Antifoaming agents are included in a variety of foods such as diet Pepsi, diet Coke, Sprite, and chicken nuggets. Antifoaming agents are also used medicinally to relieve bloating, because they cause small bubbles to form into large bubbles, which are passed more easily. They are added to food to reduce the formation of scum, or to avoid excessive frothing or boiling over.

When used in Engine Motor oil as an oil additive to the base stock of oil, antifoam agents prevent the oil from foaming and frothing during high speed mechanical agitation.