Exhibit 4.12

                             CERTIFICATE OF TRUST OF
                            OMNICARE CAPITAL TRUST II
                            -------------------------

     THIS CERTIFICATE OF TRUST of Omnicare Capital Trust II (the "Trust"), dated
February 7, 2003, is being duly executed and filed to form a statutory trust
under the Delaware Statutory Trust Act (12 Del. C. 'SS' 3801 et seq.)(the
"Act").

     1. Name. The name of the statutory trust formed hereby is Omnicare Capital
Trust II.

     2. Delaware Trustee. The name and business address of the trustee of the
Trust in the State of Delaware is Chase Manhattan Bank USA, National
Association, 500 Stanton Christiana Road, FL3-OPS 4, Newark, Delaware, 19713,
Attention: Institutional Trust Services.

     3. Effective Date. This Certificate of Trust will be effective as of its
filing.

     IN WITNESS WHEREOF, the undersigned has executed this Certificate of Trust
as of the date first-above written in accordance with Section 3811(a) of the
Act.

                                CHASE MANHATTAN BANK USA, National
                                Association, not in its individual capacity, but
                                solely as trustee


                                By: /s/ John J. Cashin
                                    --------------------------------------------
                                    Name:  John J. Cashin
                                    Title: Vice President