Abstract: Disclosed is a method for staunching blood flow from an acutely bleeding gastrointestinal lesion. The method comprises introducing, into the gastrointestinal tract, a tamponading mass having ferromagnetic properties. A suitable tamponading mass is a mixture of finely divided iron particles and vegetable oil which may be introduced through an endoscopic catheter. Once in the gastrointestinal tract, the tamponading mass is moved as necessary to cover and press upon the bleeding lesion by a magnetic field generated outside the body, e.g. by an electromagnet. The positioning is under the direct visual control of the endoscopist.