Oxytetracycline is mainly used to treat a variety of infectious diseases caused by Rickettsia, Mycoplasma, Chlamydia and other microorganisms, such as typhus, respiratory tract infection and urinary system infection caused by Mycoplasma, psittacosis caused by Chlamydia, sexually transmitted diseases, etc., and is also applicable to the treatment of special bacterial infectious diseases such as brucellosis, cholera, pestis, etc. These diseases are mostly caused by specific microorganisms, and drugs achieve therapeutic effects by blocking the survival of pathogens