A catheter includes: a catheter body defining: a first lumen communicating with a first distal opening, and a second lumen communicating with a second distal opening. The second distal opening is positioned proximal of the first distal opening. A flow path cross-sectional area of the first lumen in at least a part of a distal region of the catheter body that is distal of the second distal opening is larger than a flow path cross-sectional area of the first lumen in a proximal region of the catheter body that is proximal of the second distal opening.
