In this research, we formulated new chemotherapeutic copper nanoparticles (Cu NPs) containing Allium noeanum Reut. ex Regel leaf for treating human endometrial cancer. For investigating the antioxidant activitiy, the 2,2-diphenyl-1-picrylhydrazyl (DPPH) test was used. MTT test was used on normal (Human umbilical vein endothelial cells (HUVECs)) and human endometrial cancer (Ishikawa, HEC-1-A, HEC-1-B, and KLE) cell lines for comparing the anti-human endometrial cancer properties of Cu(NO3)2, A. noeanum leaf aqueous extract, and copper nanoparticles. Copper nanoparticles had high cell death and anti-human endometrial cancer effects against Ishikawa, HEC-1-A, HEC-1-B, and KLE cell lines. The IC50 of A. noeanum leaf aqueous extract and copper nanoparticles against HEC-1-B cell line were 548 and 331 µg/mL, respectively; against HEC-1-A cell line were 583 and 356 µg/mL, respectively; against KLE cell line were 609 and 411 µg/mL, respectively; and against Ishikawa cell line were 560 and 357 µg/mL, respectively. Among the above cell lines, the best result of anti-human endometrial cancer properties of copper nanoparticles was gained in the cell line of HEC-1-B. This study indicated excellent anti-human endometrial cancer potentials of copper nanoparticles containing A. noeanum in the in vitro condition. [ABSTRACT FROM AUTHOR]