Two novel complexes of Pd(II) involving vitamin B6 compounds have been synthesized. They are compatible with the compositions Pd(P.H.)2 C2(P = pyridoxol) and Pd(PL.H)2 C2(PL = pyridoxal). The complexes inhibited the growth as well as the biosynthesis of RNA, DNA, and protein of E. coli B-766. Photoacoustic spectral (PAS) measurements showed that the complexes bound to DNA of the bacteria and were present only in the kidney of treated mice. The complexes inhibited the incorporation of 3H-thymidine as well as 14C-leucine in the DNA and protein, respectively, of liver cell cultures (BL8L). The inhibition of cell division of Walker-S-cells and human lymphocytes by the complexes was highly significant.