The present invention relates to polyC:poly(G/l) dsRNAs for triggering innate immunity, in particular through toll-like receptor 3 (TLR-3) and, optionally, RIG-I or RIG-I— like receptors (RLRs), as well as compositions and medicaments containing such dsRNAs, methods for their production and their use in medicine, especially immunostimulation and prevention and/or therapy of infections and tumor diseases.