Hepatocellular carcinoma is a particularly dangerous and severe kind of liver cancer. Many anticancer drugs fail to complete the treatment of hepatocellular carcinoma without any side effects. There should be appropriate and without side effective treatments for hepatocellular carcinoma. The objective of the current study was to evaluate how quercetin and silymarin in a niosomal formulation affected hepatocyte carcinoma caused by diethylnitrosamine. Five groups were created from the thirty male rats. Normal control (untreated group), tumor group (administered dimethylnitrosoamine 200 mg/kg), treatment group I (administered 50 mg/kg of niosomal encapsulated quercetin), treatment group II (administered 50 mg/kg of niosomal encapsulated silymarin), and treatment group III (administered 50 mg/kg of niosomal encapsulated quercetin + silymarin). Then, biochemical estimation, serum analysis, and histopathological examination were carried out. Treatment group III, treated with niosomal encapsulation of a combination of quercetin + silymarin 50 mg/kg, demonstrated the significant restoration of alpha-fetoprotein and carcinoembryonic antigen and also antioxidants like superoxide dismutase and nitric oxide. The histopathological examination showed improved liver architecture in this group compared to other treatment groups. Our findings revealed that a potent anticancer effect was observed in treatment group III as niosomal formulation increased the bioavailability of the drug within the body. In order to completely understand the underlying processes and evaluate the therapeutic effectiveness of these chemicals in the therapy of hepatocellular carcinoma, further investigation and clinical trials are required.