Patients with viral infections can take antiviral drugs under the guidance of a physician, but not all viral infections need to be used. Clinically, self-limiting diseases caused by viral infections, such as upper respiratory tract infections, are mostly treated symptomatically with antipyretics for fever and phlegmolytic drugs such as aminoglutethimide hydrochloride for coughing. For heavier viral infections, and non-self-limiting diseases such as hepatitis B, HIV and herpes virus, antiviral drugs can be used: 1. Nucleosides: such as ribavirin, entecavir, tenofovir, etc. Ribavirin has a broad antiviral spectrum and inhibits a variety of DNA and RNA viruses, such as hemorrhagic fever virus. Entecavir is currently the first-line antiviral treatment for hepatitis B. Tenofovir can treat both hepatitis B and AIDS; 2, non-nucleoside class: such as amantadine, sodium phosphonate, etc. Amantadine is an ion channel inhibitor, early application of anti-influenza virus, but the current resistance rate is high. Sodium phosphonate has a broad antiviral spectrum and can be used for cytomegalovirus and herpes simplex virus infection; 3, immunomodulatory classes: including interferon, transfer factor and interleukin-2, etc., mainly through the inhibition of viral proliferation, growth, replication and enhance immunity to achieve antiviral effects. Interferon is commonly used in the treatment of hepatitis B and malignant tumors; 4. Polysaccharides: such as mannoprotein and dextran sulfate, can enhance the immunity of patients, and can also directly inhibit viral activity or inhibit viral replication.