Tegio is an anti-tumor drug mainly used for the treatment of unresectable locally advanced or metastatic gastric cancer and so on. The main side effects include leukopenia. Tegio is a fluorouracil derivative anticancer agent, which can exert similar efficacy to fluorouracil intravenous infusion. The main mechanism of action is by affecting DNA synthesis. It is mainly used for the treatment of locally advanced or metastatic gastric cancer that cannot be surgically resected, and the treatment of some inoperable breast, colon and pancreatic cancers. The main side effects of the drug include gastrointestinal reactions such as nausea, vomiting and diarrhea, leukopenia and thrombocytopenia. In addition, it should be noted that the use of the drug should be contraindicated in people with a history of severe allergies, severe bone marrow suppression, and severe liver and kidney dysfunction. The use of specific drugs should be under the guidance of a doctor.