Interleukin-1 (IL-1) and its family members play a central role in innate immunity and inflammation. The IL-1 family includes 7 ligands (IL-1α, IL-1β, IL-18, IL-33, IL-36α, β, γ), three receptor antagonists (IL-1Ra, IL-36Ra, IL-38), and an anti-inflammatory cytokine (IL-37). The IL-1 receptor family consists of 11 members, including decoy receptors and negative regulators. These molecules are tightly regulated to balance the amplification of innate immunity and the prevention of uncontrolled inflammation. IL-1α and IL-1β are produced by different cell types and have distinct biological properties, with IL-1α acting as an alarmin during tissue damage and IL-1β being activated by caspase-1. IL-1 family members are involved in the differentiation and function of innate and adaptive lymphoid cells, including T cells, NK cells, and ILCs. They also influence metabolic processes and are implicated in various diseases, such as autoinflammatory disorders, cancer, and metabolic syndrome. Therapeutic strategies targeting IL-1, such as anakinra and canakinumab, have shown significant efficacy in treating these conditions. The understanding of the IL-1 family's role in immunity and inflammation opens up new avenues for therapeutic interventions.Interleukin-1 (IL-1) and its family members play a central role in innate immunity and inflammation. The IL-1 family includes 7 ligands (IL-1α, IL-1β, IL-18, IL-33, IL-36α, β, γ), three receptor antagonists (IL-1Ra, IL-36Ra, IL-38), and an anti-inflammatory cytokine (IL-37). The IL-1 receptor family consists of 11 members, including decoy receptors and negative regulators. These molecules are tightly regulated to balance the amplification of innate immunity and the prevention of uncontrolled inflammation. IL-1α and IL-1β are produced by different cell types and have distinct biological properties, with IL-1α acting as an alarmin during tissue damage and IL-1β being activated by caspase-1. IL-1 family members are involved in the differentiation and function of innate and adaptive lymphoid cells, including T cells, NK cells, and ILCs. They also influence metabolic processes and are implicated in various diseases, such as autoinflammatory disorders, cancer, and metabolic syndrome. Therapeutic strategies targeting IL-1, such as anakinra and canakinumab, have shown significant efficacy in treating these conditions. The understanding of the IL-1 family's role in immunity and inflammation opens up new avenues for therapeutic interventions.