A device for treating a blood vessel, comprising: a catheter adapted to be inserted into a blood vessel to be treated; a selection member associated with said catheter to prevent a blood flow in at least one given section of said blood vessel, wherein said selection member comprises a first inflatable element and a second inflatable element, said given section being delimited longitudinally by said first and second inflatable elements (9, 10); a self-perfusion means associated with said catheter to put a first portion of said blood vessel upstream of said given section in fluid communication with a second portion of said blood vessel downstream of said given section; a treatment system associated with said catheter to cause a drug in fluidic state to flow, through said catheter, at least down to said given section wherein said selection member is mounted on said catheter so as to delimit on said catheter an active portion adapted to radially face said given section of said blood vessel, wherein said treatment system comprises one or more treatment lumina extending within said catheter and ending in a plurality of treatment holes at said active portion to deliver said drug, wherein said one or more treatment lumina and said plurality of treatment holes allow said drug in fluidic state to come to contact with said given section; and one or more return lumina starting in a plurality of return holes at said active portion and extending within said catheter to allow at least a blood outflow from said given section when said drug is delivered into said given section and, after a treatment, a drug outflow from said given section and re-introduction of the blood previously withdrawn from said given section. a catheter adapted to be inserted into a blood vessel to be treated; a selection member associated with said catheter to prevent a blood flow in at least one given section of said blood vessel, wherein said selection member comprises a first inflatable element and a second inflatable element, said given section being delimited longitudinally by said first and second inflatable elements (9, 10); a self-perfusion means associated with said catheter to put a first portion of said blood vessel upstream of said given section in fluid communication with a second portion of said blood vessel downstream of said given section; a treatment system associated with said catheter to cause a drug in fluidic state to flow, through said catheter, at least down to said given section wherein said selection member is mounted on said catheter so as to delimit on said catheter an active portion adapted to radially face said given section of said blood vessel, wherein said treatment system comprises one or more treatment lumina extending within said catheter and ending in a plurality of treatment holes at said active portion to deliver said drug, wherein said one or more treatment lumina and said plurality of treatment holes allow said drug in fluidic state to come to contact with said given section; and one or more return lumina starting in a plurality of return holes at said active portion and extending within said catheter to allow at least a blood outflow from said given section when said drug is delivered into said given section and, after a treatment, a drug outflow from said given section and re-introduction of the blood previously withdrawn from said given section. wherein said selection member is mounted on said catheter so as to delimit on said catheter an active portion adapted to radially face said given section of said blood vessel, wherein said treatment system comprises one or more treatment lumina extending within said catheter and ending in a plurality of treatment holes at said active portion to deliver said drug, wherein said one or more treatment lumina and said plurality of treatment holes allow said drug in fluidic state to come to contact with said given section; and one or more return lumina starting in a plurality of return holes at said active portion and extending within said catheter to allow at least a blood outflow from said given section when said drug is delivered into said given section and, after a treatment, a drug outflow from said given section and re-introduction of the blood previously withdrawn from said given section.