Antiviral medicines are medications that are used to treat viral infections. Viruses are tiny infectious agents that can cause a wide range of illnesses, from the common cold to more serious conditions such as HIV/AIDS and COVID-19. Unlike bacteria, viruses cannot be treated with antibiotics, so antiviral drugs are specifically designed to target and inhibit the replication of viruses. Antiviral drugs can be classified into different groups based on the type of virus they target and their mechanism of action. Examples of antiviral drugs include acyclovir, which is used to treat herpes simplex virus infections, and oseltamivir, which is used to treat influenza. Antiviral drugs can help reduce the severity and duration of an illness, but they are not always effective, and some viruses such as HIV and COVID-19 are particularly difficult to treat with antiviral drugs.