Cetuximab is a monoclonal antibody against human epidermal growth factor receptor, the main action of which is to bind to the epidermal growth factor receptor and block the binding of epidermal growth factor receptor with other ligands for anti-tumor purpose. Various malignant tumor cells, such as rectal cancer cells and gastric cancer cells, highly express the epidermal growth factor receptor on their surface, and through the abnormally enhanced tyrosine kinase activity of this receptor, they deliver growth signals to tumor cells, causing them to proliferate without restriction and without death. Cetuximab binds to the epidermal growth factor receptor on the surface of tumor cells, prevents the binding of this receptor to other ligands, inhibits tyrosine kinase activity, reduces proliferation signaling to tumor cells, induces tumor cell death, and achieves the goal of killing tumor cells. Cetuximab is mainly used clinically for the treatment of metastatic rectal cancer, gastric cancer and other gastrointestinal tumors, either alone or in combination with chemotherapy, and also for the treatment of squamous cancers of the head and neck, such as nasopharyngeal carcinoma and other tumors.