An internal prosthesis for treating inguinal hernias, the prosthesis comprising a flat portion 1 divided into two asymmetric portions 1, 1 by means of a central dividing line 2, each of the asymmetric portions 1, 1 being formed of a semi-oval body 11, 11 provided at their lower edge with an oval slot 12, 12 from which extends an oval and oblong lower wing 13, 13. Each of the asymmetric portions 1, 1 is further capable of being helicoidally folded over the other to define a pair of double-resistance areas 110, 130 such that the prosthesis is capable of treating two of the areas most commonly affected by hernias； an upper double-resistance area 110 obtained by overlapping of the semi-oval surfaces 11, 11, and a lower double resistance area 130 obtained by overlapping of the lower wings 13, 13. The heliocoidal folding of the asymmetric portions 1, 1 also causes the oval slots 12, 12 formed at the lower edge of the asymmetric bodies 11, 11 to overlap to form an oval opening 120 for receiving the spermatic cord 5.
