Abstract: A device 10 for use in the treatment of erectile dysfunction or for penile exercise includes an elongate vessel 12 defining a vacuum chamber 16. The vessel 12 has at one end thereof a mouth opening 18 leading into the vacuum chamber 12. The vacuum chamber 16 is shaped and dimensioned to receive a penis. The device 10 further includes a valve arrangement 14 positioned at or towards the other end of the vessel 12. The valve arrangement 14 incorporates both a non-return valve 34 to permit air to be extracted from and a vacuum to be drawn in the vacuum chamber 16, and a selectively operable vacuum relief valve.