Abstract: An inflatable mouthpiece includes an outer cover, an air bladder, a filter, a turnable cover and a liquid container. The air bladder is disposed in a space defined between the outer cover and the turnable cover. The liquid container is placed inside the air bladder. Soda powder is sprinkled on the liquid container within the air bladder. The liquid container is fitted in to a hemispherical recess of the outer cover such that a part of the container wall projects in a space of the outer cover. When the turnable cover is turned in a set direction, a press plate of the turnable cover contacts and presses the liquid container to cause a citric acid therein to flow out to react with the soda powder for producing a carbon dioxide gas to quickly inflate the air bladder.