Human CCL11 (C-C motif chemokine ligand 11), also known as eotaxin-1, is a member of the CC chemokine family that plays a central role in regulating eosinophil recruitment and type 2–associated immune responses. CCL11 is produced primarily by epithelial cells, fibroblasts, endothelial cells, smooth muscle cells, and activated immune cells in response to Th2-associated cytokines such as IL-4 and IL-13, as well as inflammatory stimuli. It functions predominantly through the CCR3 receptor to promote chemotaxis and activation of eosinophils, and also influences basophils and certain Th2 lymphocytes. In healthy individuals, circulating CCL11 levels are typically low, but concentrations increase during allergic inflammation, parasitic infection, and certain chronic inflammatory conditions. Elevated CCL11 has been implicated in asthma, allergic rhinitis, atopic dermatitis, eosinophilic esophagitis, inflammatory bowel disease, and some neuroinflammatory and aging-related processes. In clinical and translational research, human CCL11 serves as an important biomarker of eosinophilic inflammation and Th2-driven immune responses and represents a potential therapeutic target for allergic and eosinophil-associated diseases.