Sinomenine (SN), a pure compound extracted from the Sinomenium acutum plant, has been found to inhibit T- and B-lymphocyte activation, proliferation and function and to interfere with the differentiation, recruitment and function of several other cell types, such as dendritic cells (DC). SN has demonstrated its potential anti-inflammatory role for treating immune-related disorders in experimental animal models and in some clinical applications. This review will summarize its potential effects, mechanisms and applications.