A method of treating a tumor or a viral disease by administering to a human the following 2′,5′-oligoadenylate analog: Wherein m is 0; n is 0 or 1; R1 is alkoxy substituted by hydroxyl, mercapto, alkylthio substituted by hydroxyl or X1—X2—X3—S—; R2, R3, R4, R5 and R6 are hydroxyl, mercapto, alkylthio substituted by hydroxyl or X1—X2—X3—S—; R7 is oxygen, sulfur, —NH—, or —O(CH2CH2O)q-, wherein q is 2 to 6, or oxyalkyleneoxy; R8 is hydrogen or a 5′-phosphorylated oligonucleotide which has one hydroxyl removed from the 5′-phosphoric acid; E1 is K2; E2 is K1; E3 is K2 or K3 and E4 is K1, K2 or K3; K1 is K2 is K3 is B is adeninyl; A is alkylene; D is alkyl or alkenyl; X1 is alkyl or phenyl; X2 is —C(═O)O—, —OC(═O)— or —C(═O)S—; and X3 is alkylene.