Polyinosinic–polycytidylic acid potassium salt is widely used in biomedical research as a synthetic analog of double-stranded RNA (dsRNA). It is commonly employed to stimulate the immune system by mimicking viral infections, making it a valuable tool in studying antiviral responses and immune activation. In immunology, it is used to induce the production of interferons and other cytokines, helping researchers understand the mechanisms of innate immunity. Additionally, it is utilized in cancer research to enhance the immune response against tumors, often as an adjuvant in immunotherapy. Its ability to activate toll-like receptors (TLR3) and other pattern recognition receptors makes it a key component in vaccine development and studies on autoimmune diseases.