Exhibit 99.1

                                                              September 10, 2002


Genesis Health Ventures, Inc.
101 East State Street
Kennett Square, Pennsylvania  19348
Attention:  George V. Hager, Jr.

Gentlemen:

                  Reference is made to the Agreement and Plan of Merger (the
"Merger Agreement") dated as of July 28, 2002 by and among Genesis Health
Ventures, Inc. ("Genesis"), Geneva Sub, Inc. ("Sub") and NCS HealthCare, Inc.
("NCS"). As you know, Omnicare, Inc. ("Omnicare") has (i) commenced a tender
offer (the "Tender Offer") to purchase all of the outstanding shares of Class A
Common Stock and Class B Common Stock of NCS for $3.50 per share in cash
pursuant to Section 14(d) of the Securities Exchange Act of 1934, as amended and
the rules and regulations thereunder and (ii) made various proposals
constituting Acquisition Proposals, which proposals, together with the Tender
Offer, are hereinafter referred to as the "Omnicare Proposals." All capitalized
terms used but not otherwise defined herein shall have the meaning ascribed to
such terms in the Merger Agreement.

                  I am writing this letter to confirm that, in response to our
verbal request, Genesis and Sub have agreed to waive the requirements of clauses
A (II) and (III) of Section 5.3(c)(iv) of the Merger Agreement, solely for the
purpose of permitting NCS to enter into discussions with Omnicare relating to
the Omnicare Proposals. The foregoing waiver of clause A (III) relates solely to
the entering into of discussions with Omnicare, and not to the furnishing of any
non-public information to Omnicare. In the event non-public information is to be
furnished to Omnicare by NCS, Omnicare must first execute a confidentiality
agreement pursuant to clause A (III).

                  NCS understands and acknowledges that the foregoing waiver is
limited solely to the actions set forth above and shall in no manner affect any
of its other obligations under the Merger Agreement, which shall remain in full
force and effect, unaffected by the terms of this letter agreement.

                  If this letter agreement reflects your understanding of the
foregoing matters, please sign and deliver a copy of this letter agreement to
the undersigned whereupon this letter agreement shall become a valid and binding
agreement among us.

                                        Very truly yours,

                                        NCS HEALTHCARE, INC.


                                        By: /s/ Jon H. Outcalt
                                        ----------------------------------------
                                            Jon H. Outcalt
                                            Chairman of the Board

Accepted and Agreed as of
this 11th day of September, 2002

GENESIS HEALTH VENTURES, INC.


By: /s/ George V. Hager, Jr.
   ---------------------------------------------


GENEVA SUB, INC.


By: /s/ George V. Hager, Jr.
   ---------------------------------------------



cc:      Mark Gordon, Esq.
         Megan L. Mehalko, Esq.
         H. Jeffrey Schwartz, Esq.