Patent ID: 7748388

Claim:
A method comprising injecting a preparation into a predetermined mucosal tissue to elevate the mucosal tissue, and endoscopically resecting the mucosal tissue portion, wherein the preparation comprises a gelled high viscosity substance comprising 0.25 to 0.4 weight/volume percent of hyaluronic acid having a viscosity-average molecular weight of 1,900,000 to 2,200,000 or a salt thereof, the gelled high viscosity substance is dissolved in an aqueous solution containing 0.8 to 1 weight/volume percent of sodium chloride, and the preparation is injected through an injection needle having a diameter of 20 to 22 G, and an effective length of a tube of the injection needle is 1,000 mm or more such that the inflow rate of the injectable preparation, when injected at a pressure of 2 to 3 atmospheres through said injection needle, is 0.05 to 0.1 ml/sec.