In addition to being used as an anthelmintic, levamisole hydrochloride also has immunomodulatory effect, which can effectively improve the immune function of patients. Levamisole can regulate the immune function, mainly on T lymphocytes, to induce the early differentiation and maturation of T cells into functional T cells, so as to promote the normal function of T cells. It can also strengthen the phagocytosis and chemotaxis of macrophages, so as to improve the activity of natural killer cells, produce endogenous interferon, improve the immune function and make it normal, and effectively prevent the progress of pneumonia, Improve cough, lung sounds and other symptoms. In addition, after the immune function of children is weakened, levamisole hydrochloride can increase the content of total complement in blood, especially the production of IgG and IgA, so as to improve the immune effect of respiratory tract Ru membrane, and play the role of virus resistance and anti bacterial infection. Levamisole can not only regulate the immune function, but also restore the immune function. It can show two-way regulation for the abnormal humoral immune function, make it tend to normal development, and help the low cellular immune function return to normal.