Doxycycline is a medicine used to treat some infections, when some pathogenic microorganisms infect the human body, and the corresponding symptoms appear, you can choose doxycycline for treatment. Doxycycline is also selective and is generally used to treat infections of mycoplasma and chlamydia, and rickettsia and spirochete infections are also often selected for doxycycline. Doxycycline can also be used for brucellosis, but it is usually combined with rifampin or other drugs, and is not very effective when applied alone. Doxycycline can be taken orally, is relatively inexpensive, and can be chosen when Mycoplasma pneumoniae and Chlamydia pneumoniae infections are present. Lyso-urea ureaplasma and Chlamydia trachomatis infections, which often lead to genitourinary infections, are also perfectly fine when doxycycline is chosen. The other options are rat bite fever and soft chancre. If you are allergic to penicillin in the case of syphilis, you can also choose doxycycline for treatment.