The purified frog skin peptides were tested on leukemic patients lymphocytes, which revealed effects of cytotoxicity. Four frogs (Rana ridibunda) were stimulated by single intra-peritoneal injection of norepinephrine-HCl . Five different peptides;1(18) A, 2(19) L, 3(20) I,4(21) E and 5(22) Y were isolated and quantified. The peptide 3(20)I had 5.87% of hemolysis, while healthy human lymphocytes cytotoxic activity was for 2(19)L with inhibition( -10.4%).All peptides were subjected to polyacrylamide gel electrophoresis. The results revealed peptides 1(18)A, 2(19)L, 3(20)I which appeared as low as 10 KDa  marker. Theoretically, the whole polypeptide had a molecular weight 7488.61 Dalton and contained on 62.405 amino acid (a.a). The peptide 4(21)E had a highest inhibitory effect(46%) on tumor cell line L20B. Furthermore , peptides effects on acute  and  chronic  myeloid  lymphocytic  leukemia  patients cell cultures  revealed  peptides selectivity  in  their  action according  to  their net charge  and functional  group as  reactant  proton  donor by the  evidence  of peptide 5(22)Y, 16.22 Dalton  so  it  was  either N—terminus (--NH₂) or  C—terminus (--OH)  that  led  to  cross  cell  membrane then acted as antigen mediated and activated  cells in a high significant  value (-142.37± 47.69)for acute myeloid  lymphocytic leukemia .Both  of peptides  3(20) I  and  2(19) L were revealed  a  highly significant  differences  within  Chr.40  and Chr. 22 of  inhibition  effects  by testing  volumes 15 µl and 10 µl . Those inhibition  effects  were due to  peptides  reaction  with  mitochondrial  membrane  which  led  to apoptosis . Conclusion; Frog skin peptides have a therapeutically worth for malignant diseases. Also some of peptides were activated lymphocytes may to cure immunodeficiency.