A bottle opener has two parts which are slidable relative to one another and between which there is a pressure chamber. A corkscrew extends from one of these parts which has a cavity therein accommodating a valve and a gas cartridge. When the corkscrew is embedded in a cork in the neck of a bottle and the valve is actuated gas flows from the gas cartridge to the pressure chamber to move the two parts away from one another so that the cork is extracted.