A herbal composition comprising a therapeutically effective amount of the extract of Piper betle leaves as an active ingredient either alone, or with a pharmaceutically acceptable excipient. A process for the preparation of the herbal composition is provided. The herbal composition is adapted for the treatment of chronic myeloid leukemia (CML; chronic myelogenous leukemia) showing resistance to treatment with imatinib (Gleevec.RTM. or Glivec.RTM.).