FIELD : medicine.SUBSTANCE : invention relates to medical equipment, specifically to an end effector for stapling tissue. End effector for stapling tissue comprises a cartridge, staples, an anvil, a staple drive and a firing member. Cartridge comprises a longitudinal row of staple cavities. Staples are adapted for extraction from the staple cavities. Each staple comprises a base, a pair of legs extending from the base, and a plane formed by the pair of legs. At least one of the legs comprises at least one barb extending circumferentially around said leg by less than 360 degrees, while the barb extends beyond the plane formed by the legs, so that the barb extends inside the plane of the staple and out of the plane of the staple formed by said legs, and wherein each leg comprises a tip configured to pierce tissue. Anvil is configured to deform the staples. Staple drivers are configured to move within the cavities and raise the staples to the anvil. Firing member is configured to raise the staple driver to the anvil. Firing member comprises a first portion configured to engage the anvil, and a second portion configured to engage the cartridge. Firing member is configured for relative arrangement of the anvil and the cartridge, wherein the barb includes a first surface and a second surface, which extend from a portion of the perimeter of the leg of the staple and around it and extends beyond said plane formed by the legs of the staple, wherein the first surface and the second surface converge at the edge, which is arcuate.EFFECT : invention is characterised by the fact that the barb not only supports tissue inside the plane formed by the legs of the staple, but also supports tissue outside said plane.6 cl, 73 dwg