The use of reagents and synthetic dyes products in the textile industry makes the effluents originated in the industrial process have a high danger of contamination in the receiving bodies in surface water or soil. In search of a solution for the treatment of these discharges, the research has the objective of decreasing the concentration of the BRL blue dye, by means of silver nanoparticles (AgNPs) synthesized according to a green chemistry route. The methodology consists on synthesizing AgNPs by using Petroselinum crispum (parsley) extract as reducing and stabilizing agent. Characterization of the prepared samples revealed in the best case AgNPs having 24.25 nm size. These AgNPs have been used for the treatment of model effluent samples, obtaining a reduction of the BRL blue dye until 80.46%. The obtained result shows that the prepared AgNPs can be successfully used for the treatment of residual waters of one of the industries that have been causing high contamination lately, and the results is more promising considering that the AgNPs have been obtained with an environmentally friendly method.