Method of taking out liquid present inside subject therefrom

A method of taking out liquid present in a body cavity of a subject from the body cavity to an outside of the subject, the method comprising:

• a first step of inserting a tool through the body cavity of the subject to reach a target site in the body cavity, the tool pressing a wall surface of the body cavity;
• a second step of adjusting a body position of the subject such that the wall surface of the body cavity including the target site intersects with a direction of gravitational force and the liquid present in the body cavity gathers on the wall surface intersecting with the direction of gravitational force;
• a third step of forming a recess concaved on the wall surface in the direction of the gravitational force by making the tool press the wall surface of the body cavity;
• a fourth step of accumulating the liquid present in the body cavity in the recess;
• and
• a fifth step of taking out, outside of the body of the subject, the liquid accumulated in the recess.