The objective of this research is to evaluate the efficiency of Opuntia ficus-indica as a natural coagulant in the treatment of gray wastewater. The research is experimental and of explanatory scope that consists of collecting gray water to elaborate a block sample design and its subsequent testing in the jar test equipment; different doses of coagulant powder were applied after the process of collection, reduction, drying, grinding of the stalk and sieving of the flour. As a result, 1.625 g/l was obtained as the optimum dose of natural coagulant for the treatment of graywater, with which greater efficiency was achieved in the removal of pollutants; thus, for turbidity 90%, TSS 83%, BOD 74%, COD 38% and Nitrite 73%; it is concluded that Opuntia ficus-indica as a natural coagulant is efficient for the treatment of graywater and its subsequent use.