Doxycycline hydrochloride tablets are not recommended for stomach pain. Doxycycline hydrochloride is a tetracycline antibiotic, and its mechanism of action is to specifically bind to the A position of the 30 S subunit of bacterial ribosomes, inhibit the growth of peptide chains and affect the synthesis of bacterial proteins. It is a broad-spectrum bacteriostatic agent with bactericidal effect at high concentration. It is more effective against Gram-positive bacteria than Gram-negative bacteria, but Enterococcus spp. are resistant to it. Doxycycline Hydrochloride is mainly used in the treatment of respiratory tract infections, tonsillitis, chronic bronchitis, pneumonia, biliary tract infections, lymphadenitis, cellulitis and urinary tract infections, etc. It can also be used in the treatment of typhus fever, typhoid fever, kangaroo fever, mycoplasma pneumonia and cholera. In addition, it can prevent falciparum malaria and leptospirosis. Doxycycline Hydrochloride can cause gastrointestinal adverse reactions such as nausea, vomiting, abdominal distension, abdominal pain, diarrhea, etc. Therefore, Doxycycline Hydrochloride is not recommended for patients with stomach pain to avoid causing or aggravating symptoms such as stomach pain. Doxycycline Hydrochloride is recommended to be taken under the guidance of a doctor and should not be used without authorization.