A liquid dispensing device and the method of dispensing liquid are disclosed. The device is uniquely suited to meet the requirements of hospitals and other institutions for long shelf life in inert condition and ready activation when needed. The device includes a hollow gas- and liquid-tight casing (preferably spherical or cylindrical), a flexible gas- and liquid-tight membrane disposed entirely across the casing interior dividing the interior into a propellant chamber and a liquid chamber; an outlet port from the liquid chamber; two mutually reactive chemicals in the propellant chamber but separated by a barrier; and a member to breach the barrier and permit the chemicals to come into contact; the two chemicals being reactive upon contact to form a propellant gas. The propellant gas thereupon expands against the membrane, moves the membrane to enlarge the propellant chamber, decrease the liquid chamber, and expel the contained liquid from the liquid chamber through the outlet port. The barrier may be breached in any convenient manner, as by breaking a frangible barrier or perforating a perforable one. Preferably at least one of the chemicals is in liquid form, and one is a Group I or II metal carbonate or bicarbonate while the other is an acid, acid anhydride or acid salt; the most preferred combination is sodium carbonate and citric acid.