The invention relates to a blood line (108) comprising an infusion site (145) intended to inject into the line a solution, comprising: —a first main channel (200) having a first passage section, —a second main channel (220) having a second passage section, —means for the formation (210) of a turbulence area located downstream from the first main channel, located upstream from the second main channel, these formation means comprising a first fluid passage means (224) defining a reduction (225) in the passage section and whose smallest passage section is smaller than the first passage section and smaller than the second fluid passage section, —a secondary channel (230) comprising an inlet (231) for letting in the solution and an outlet (232) in fluid communication with the first main channel or the means for the formation of a turbulence area or the second main channel.