Interleukin-11 (IL-11) is a cytokine belonging to the IL-6 family that plays a crucial role in various physiological processes, including hematopoiesis, bone metabolism, and gastrointestinal mucosal protection. In rats, IL-11 is primarily produced by stromal cells in the bone marrow and other cell types, such as fibroblasts and endothelial cells. IL-11 exerts its biological effects by binding to the IL-11 receptor complex, which consists of IL-11Rα and gp130 subunits, leading to the activation of signaling pathways such as the JAK-STAT pathway. IL-11 has been shown to promote the growth and differentiation of hematopoietic progenitor cells, stimulate platelet production, and enhance bone formation. Additionally, IL-11 has anti-inflammatory properties and is being investigated for its potential therapeutic applications in conditions such as osteoporosis and inflammatory bowel disease.