IL-11, a member of IL6 family of cytokines, exerts a wide range of biological effects on various cell types including hematopoietic cells, hepatocytes, adipocytes, neurons, and osteoblasts. IL-11 works synergistically with other growth factors, which include SCF, IL-4, IL-3, IL-7, IL-12, IL-13, and GM-CSF to stimulate the proliferation of cells from several hematopoietic lineages. The binding of IL-11 to IL-11 receptor (IL-11R) induces membrane bound gp130 homodimerization and triggers STAT3 phosphorylation by JAK. IL-11 shares the common receptor subunit gp130 with IL-6, IL-27, LIF, OSM, CNTF, CT-1, CLC, and NP. Female mice deficient in the IL-11R revealed an important role for IL-11 in embryonic implantation. Additionally, IL-11 shows anti-inflammatory activity in models of inflammatory bowel disease, chemotherapy induced oral mucositis, and inflammatory arthritis. IL-11 and IL-13 are highly expressed in asthmatic airways (Th2 response), and IL-11 can inhibit Th1 responses and inhibits the production of Th1 cytokines such as IL-12 and shifts inflammation in the Th2 direction. Elevated IL-11 expression is associated with tumor grade and invasion in gastric cancer. Recombinant human IL-11 has been clinically approved to improve platelet recovery after chemotherapy-induced thrombocytopenia.