This disclosure relates to nucleotide and nucleoside therapeutic compositions and uses in treating infectious diseases, viral infections, and cancer, where the base of the nucleotide or nucleoside contains at least one thiol, thione or thioether.本發明係關於核苷酸及核苷治療組成物及在治療感染性疾病、病毒感染及癌症中之用途,其中該核苷酸或核苷之鹼基含有至少一個硫醇、硫酮或硫醚。