We have been developing novel ultrahigh density atmospheric pressure plasma sources and succeeded in the selective killing ovarian cancer cells against normal ones. Furthermore, we have found out the plasma- activated medium (PAM) also killed glioblastoma brain tumor cells selectively against normal ones and the chemical products in the PAM have long lifetime healing effects. To clarify the mechanism, interactions of plasma with the organism and the medium where the organism belongs were investigated on the viewpoint of intracellular molecular mechanism.