A system (10) and method for generating a gas-supersaturated fluid and delivering the fluid at high delivery pressures to thereby prevent bubble nucleation is disclosed. The system (10) comprises a housing (40) for containing a removable fluid assembly (20) for housing a fluid to be gas-supersaturated and a drive assembly (30) for delivering the fluid to a delivery site. The housing assembly (40) comprises a cylinder (50) and a piston (52) which may be advanced along the inner surface of the cylinder (50) to pressurize and to deliver the fluid. To generate a gas-supersaturated fluid, the housing assembly (40) is removed from the system housing, filled with a fluid, and gas is introduced at or slightly above the desired gas partial pressure into the cylinder (50). To deliver the gas-supersaturated fluid, the fluid assembly (20) is returned to the system housing and the drive assembly (30) advances the piston (52) to increase the hydrostatic pressure to the desired delivery pressure and, after opening a valve (57), to deliver the gas-supersaturated fluid at the desired high delivery pressure to a delivery site.