From time immemorial, people have tried to treat several diseases using natural compounds, including plants. Recently, researchers proposed that plants and herbal nanoparticles possess many remedial potentials. The results of this study confirmed the ability of an aqueous extract of Allium eriophyllum Boiss leaf grown under in vitro conditions for the biosynthesis of gold nanoparticles (AuNPs) and also revealed the anti‐hemolytic anemia activity of AuNPs in an anemic rodent model. These nanoparticles were characterized using Fourier‐transform infrared spectroscopy (FT‐IR) spectroscopy, ultraviolet–visible spectroscopy, X‐ray diffraction, field‐emission scanning electron microscopy (FE‐SEM), and transmission electron microscopy (TEM). TEM and FE‐SEM images showed the biosynthesized nanoparticles as having a uniform spherical morphology and diameters in the range of 5–30 nm. In vivo design, the induction of hemolytic anemia, was done using phenylhydrazine in 40 mice. Then, the mice were randomly divided into five groups: HAuCl4, A. eriophyllum, AuNPs, untreated, and control. AuNPs significantly (p ≤ 0.01) decreased the concentration of glucocorticoid receptors in the serum, liver, and spleen, and also alkaline phosphatase, aspartate aminotransferase, alanine aminotransferase, gamma‐glutamyl transferase, total and conjugated bilirubin, cholesterol, triglyceride, low‐density lipoprotein, urea, creatinine, ferrous, ferritin, and erythropoietin in the serum increased the concentrations of superoxide dismutase, catalase, and glutathione peroxidase (GPx) in the serum, liver, and spleen and also total protein, high‐density lipoprotein, and albumin in serum in the control mice as compared to the anemic mice. Also, AuNPs significantly (p ≤ 0.01) increased the body weight; anti‐inflammatory cytokine (IL4, IL5, IL10, IL13, and IFNα) concentration; and the total platelet, white blood cells, lymphocyte, neutrophil, monocyte, eosinophil, and basophil counts and red blood cell parameters but decreased the weight and volume of the liver and spleen and their subcompartments and decreased the concentration of pro‐inflammatory cytokines (IL1, IL6, IL12, IL18, IFNY, and TNFα) compared to the untreated mice. In vitro design, using 2,2‐diphenyl‐1‐picrylhydrazyl test, revealed similar antioxidant potentials for A. eriophyllum, AuNPs, and butylated hydroxytoluene. In addition, AuNPs were similar to A. eriophyllum and had a high cell viability dose dependently against the human umbilical vein endothelial cell line. In conclusion, the results of the chemical characterization confirm that the leaves of A. eriophyllum can be used to produce AuNPs with a remarkable amount of anti‐hemolytic anemia property.