The drug of choice for the treatment of Pneumocystis carinii pneumonia is compound sulfamethoxazole tablets, often referred to as SMZ.Pneumocystis carinii pneumonia is one of the most common opportunistic infections of HIV and one of the leading causes of death. Of course, for some immunocompromised or immunodeficient patients, they are also susceptible to Pneumocystis carinii pneumonia. The first choice of treatment for Pneumocystis carinii pneumonia is of course SMZ, but for severe patients or those who have a poor effect on SMZ, it can be combined with echinocandins, also commonly known as caspofungin, to provide a combination of antimicrobial therapy, and the efficacy of treatment may be better than that of a single drug. Some patients with respiratory failure, can be appropriate with hormonal drugs.