An apparatus for containing and dispensing fluids under pressure has an inner bladder including multiple ribs. Sterilized liquid may be stored in the chamber without leaking out and being contaminated by bacteria outside. Besides, the ribs reinforce the structural strength of the inner bladder in the longitudinal direction so that the inner bladder is not recovered by the gravity after transversely compressed, and thus the access to the liquid is convenient. Further, the overall structure of the apparatus is simplified, and the production and the use of the apparatus are handy.