The present invention provides pharmaceutical compositions of SAHA and a chelatable metal compound comprising zinc or iron. In one embodiment, the invention provides a method of treating cancer and alleviating the side effects of SAHA by administering the pharmaceutical composition. In another embodiment, the present invention also provides pharmaceutical compositions of zinc SAHA chelate complexes or iron SAHA chelate complexes. In another embodiment, the invention provides methods of treating cancer by administering the pharmaceutical compositions.