Abstract: A constrictor ring for the treatment and allevation of impotence in males consisting of a ring-shaped elastic member operable to encircle the penis adjacent the user's torso, and including operating mechanism to expand it radially inwardly to engage and constrict the penis to inhibit the circulation of blood therein, thereby to encourage or maintain erection of the organ. The mechanism also includes devices for adjustably limiting the degree of constriction to which the organ may be subjected, for instantly removing all constriction if the user should feel pain or discomfort, and most importantly, for automatically releasing all constriction after a predetermined time delay sufficient to allow completion of an act of coitus, this release requiring no conscious act by the user, in order to avoid damage to the organ which otherwise could result if the user shold fall asleep or otherwise fail to release the ring.