There are two types of rejection after hematopoietic stem cell transplantation: 1. One is acute rejection. Acute rejection is mainly diarrhea, liver function impairment, and then there is a rash. The rash can be mild or severe, some are only partial skin rash, some are generalized rash, so the rash will be graded according to the area of occurrence, the degree of liver damage, and the degree of diarrhea, including grade I, II, III, and IV. By grading according to the severity, to carry out the corresponding treatment mild acute rejection, even can not go to treatment. 2, a chronic rejection. For some patients with severe grade III and IV, clinical intervention is needed; then there is chronic rejection, called chronic graft-versus-host disease, which has various manifestations, such as oral mucosal damage, another is skin damage, such as repeated rashes, skin changes, etc.; another is arthritis, and some patients show repeated liver function damage, and some patients also have cataracts, in fact, because of chronic rejection. Graft-versus-host disease is mainly a disorder of the immune system, so it will show symptoms related to connective tissue disease.