Benzathine penicillin is administered mainly to prevent recurrence of rheumatic fever and to treat streptococcal infections and syphilis. Benzathine penicillin is a compound form of penicillin, the active ingredient of which is penicillin, which has good antibacterial effects against Streptococcus spp. such as Streptococcus haemolyticus, Streptococcus pneumoniae, and Staphylococcus spp. that do not produce penicillinase. It can be used as prophylaxis for recurrence of rheumatic fever, and to treat streptococcal infections to which it is susceptible; as well as syphilis. Penicillin-induced allergic reactions, such as rash, asthma, interstitial nephritis, leukopenia, seropathic-type reactions, etc., can occur after the use of the drug, and in severe cases, even anaphylaxis may occur. Once the signs and symptoms of anaphylactic shock appear, it is necessary to immediately resuscitate in situ. The drug may potentiate the anticoagulant effect of warfarin. It can prolong the serum half-life of benzylpenicillin when aspirin and probenecid are taken at the same time. Use this drug with caution in patients with eczema, asthma, urticaria, hay fever, and other allergic diseases. The drug is contraindicated in persons with a positive penicillin skin test or a history of allergy to penicillins. Pregnant women should use the drug only when necessary, and nursing women need to suspend breastfeeding when using it. If you need to use the drug patients, please under the guidance of the doctor strictly follow the instructions of the doctor to take medication, do not self-medication.