Ligustrum is a shrub native to China and eastern Asia, although it is now cultivated in the United States. The applicable part of ligustrum is the berry, and less commonly, the seed. Ligustrum is a traditional Chinese herbal medicine. The major active constituent of lingustrum berry is ligustrin (oleanolic acid). Preliminary research suggests that ligustrin stimulates the immune system, fight infection, decreases inflammation, and protects the liver. Ligustrum is often combined with astragalus to enhance the immune system effects.