Doxycycline is a drug whose main ingredient is doxycycline hydrochloride, such as doxycycline hydrochloride tablets, etc. Taking doxycycline may cause frequent urination. Doxycycline hydrochloride is generally used to treat diseases such as Rickettsia spp, Mycoplasma spp and Chlamydia spp infections. When doxycycline hydrochloride is applied for a long period of time, it may lead to secondary infections, which can occur with drug-resistant Staphylococcus aureus, gram-negative bacteria and fungi, caused by urinary tract infections or gastrointestinal tract infections and so on. Frequent urination is usually one of the symptoms of urinary tract infections, while urinary tract infections may also present with symptoms such as urinary urgency and painful urination. If a secondary infection is caused by taking doxycycline hydrochloride, it is recommended to stop using this drug immediately. Sensitive treatment drugs can be selected according to the pathogen of the infection, and the commonly used treatment drugs include amoxicillin, furotoxin, fosfomycin, and ofloxacin. If you need to use drugs, you need to use under the guidance of a doctor, do not blindly use drugs on their own.