EXHIBIT 31.1

                                 CERTIFICATIONS

I, Gary S. Jacob, certify that:

1)  I  have   reviewed   this   annual   report  on  Form   10-K/A  of  Callisto
Pharmaceuticals, Inc.

2) Based on my  knowledge,  this  annual  report  does not  contain  any  untrue
statement of a material fact or omit to state a material fact  necessary to make
the statements made, in light of the  circumstances  under which such statements
were made,  not  misleading  with  respect to the period  covered by this annual
report;

3)  Based  on my  knowledge,  the  financial  statements,  and  other  financial
information  included  in this annual  report,  fairly  present in all  material
respects the financial  condition,  results of operations  and cash flows of the
registrant as of, and for, the periods presented in this annual report;

4)  The  registrant's  other  certifying  officer  and  I  are  responsible  for
establishing and maintaining  disclosure  controls and procedures (as defined in
Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal  control over financial
reporting  (as defined in Exchange Act Rules  13a-15(f)  and  15d-15(f)  for the
registrant and we have:

               a) Designed such disclosure  controls and  procedures,  or caused
               such disclosure  controls and procedures to be designed under our
               supervision,  to ensure that material information relating to the
               registrant,  including  its  consolidated  subsidiaries,  is made
               known to us by others within those entities,  particularly during
               the period in which this annual report is being prepared;

               b) Designed such internal  control over financial  reporting,  or
               caused such  internal  control  over  financial  reporting  to be
               designed under our supervision,  to provide reasonable  assurance
               regarding  the   reliability  of  financial   reporting  and  the
               preparation  of financial  statements  for  external  purposes in
               accordance with generally accepted accounting principles;

               c) Evaluated the  effectiveness  of the  registrant's  disclosure
               controls  and   procedures  and  presented  in  this  report  our
               conclusions  about the  effectiveness of the disclosure  controls
               and  procedures,  as of the  end of the  period  covered  by this
               report based on such evaluation; and

               d)  Disclosed  in this  report  any  change  in the  registrant's
               internal  control over financial  reporting that occurred  during
               the  registrant's  most recent fiscal  quarter (the  registrant's
               fourth fiscal  quarter in the case of an annual  report) that has
               materially  affected,  or  is  reasonably  likely  to  materially
               affect,   the   registrant's   internal  control  over  financial
               reporting.

5) The registrant's other certifying officer and I have disclosed,  based on our
most recent  evaluation of internal  control over  financial  reporting,  to the
registrant's  auditors  and the audit  committee  of the  registrant's  board of
directors (or persons performing the equivalent functions);

               a) All significant  deficiencies  and material  weaknesses in the
               design or operation of internal control over financial  reporting
               which are reasonably  likely to adversely affect the registrant's
               ability  to  record,  process,  summarize  and  report  financial
               information; and

               b) Any fraud,  whether or not material,  that involves management
               or  other   employees  who  have  a   significant   role  in  the
               registrant's internal control over financial reporting.

Date: June 6, 2005

                                        /s/ Gary S. Jacob
                                        ------------------------
                                        Gary S. Jacob
                                        Chief Executive Officer