QUANTUM HEALTH RESOURCES, INC.


                                       AND


                      U.S. BANK TRUST NATIONAL ASSOCIATION,
                                     Trustee


                               -------------------

                             Supplemental Indenture

                           Dated as of March 15, 2000
                               -------------------


                                       To


                     Indenture, Dated as of October 8, 1993,
           as supplemented and amended by the Supplemental Indenture,
                           Dated as of June 28, 1996,
                   Between Quantum Health Resources, Inc. and
             U.S. Bank Trust National Association (formerly known as
                 First Trust National Association), as Trustee,
             Relating to 4 3/4% Convertible Subordinated Debentures
                               Due October 1, 2000



--------------------------------------------------------------------------------



<PAGE>

                             SUPPLEMENTAL INDENTURE


     SUPPLEMENTAL INDENTURE (this "Supplemental Indenture"), dated as of March
15, 2000, between Quantum Health Resources, Inc., a Delaware corporation (the
"Company"), having its principal office at Two Parkwood Crossing, Suite 500, 310
East 96th Street, Suite 500, Indianapolis, Indiana, 46240, and U.S. Bank Trust
National Association (formerly known as First Trust National Association), a
Minnesota corporation, as Trustee (the "Trustee").

                             RECITALS OF THE COMPANY


     WHEREAS, the Company and the Trustee heretofore executed and delivered an
Indenture, dated as of October 8, 1993 (the "Indenture") (capitalized terms used
but not otherwise defined in this Supplemental Indenture shall have the meanings
ascribed to such terms in the Indenture), and a Supplemental Indenture, dated as
of June 28, 1996 (the "First Supplemental Indenture"); and

     WHEREAS, pursuant to the Indenture, the Company issued and the Trustee
authenticated and delivered $86,250,000 aggregate principal amount of the
Company's 4 3/4% Convertible Subordinated Debentures Due October 1, 2000 (the
"Debentures"); and

     WHEREAS, pursuant to the First Supplemental Indenture, the Debentures were
convertible into the Class B Common Stock, par value $.10 per share ("Class B
Common Stock") of Olsten Corporation, a Delaware corporation ("Olsten"); and

     WHEREAS, the Company has delivered, or caused to be delivered, to the
Trustee, an Opinion of Counsel and Officers' Certificate, each stating that this
Supplemental Indenture complies with the requirements of the Indenture; and

     WHEREAS, pursuant to the Separation Agreement, dated as of August 17, 1999,
by and among Olsten, Gentiva Health Services, Inc., a Delaware corporation
(formerly known as Aaronco Corp.) ("Gentiva"), and Adecco SA, a societe anonyme
organized under the laws of Switzerland ("Adecco"), as amended (the "Separation
Agreement"), and the Agreement and Plan of Merger dated as of August 17, 1999,
by and among Olsten, Adecco and Staffing Acquisition Corp., a Delaware
corporation and a wholly-owned subsidiary of Adecco ("Merger Sub"), as amended
(the "Merger Agreement"), on the date of the Merger each issued and outstanding
share of Olsten's Class B Common Stock, other than shares held by stockholders
exercising dissenter's rights under the General Corporation Law of the State of
Delaware, will be converted into the right to receive (i) .25 of a share of
Gentiva common stock, par value $.10 per share and (ii) either (a) $8.75 in
cash, without interest, or (b) 0.12472


<PAGE>
                                      -2-


of an Adecco American depositary share ("ADS") or (c) a combination of cash and
Adecco ADSs; and

     WHEREAS, pursuant to Sections 9.1 and 13.11 of the Indenture, the parties
hereto are entering into this Supplemental Indenture to provide that the Holder
of each Debenture outstanding at the time of the merger shall have the right
thereafter, during the period such Debenture shall be convertible as specified
in Section 13.1 of the Indenture, to convert such Debenture only into the kind
and amount of securities and cash receivable upon such merger by a holder of the
number of shares of Class B Common Stock into which such Debenture might have
been converted immediately prior to such merger as if such holder had made a
Non-Election (as defined in the Merger Agreement); and

     WHEREAS, this Supplemental Indenture has been duly authorized by all
necessary corporate action on the part of the Company.

     NOW, THEREFORE, the Company hereby covenants and agrees with the Trustee
for the equal and proportionate benefit of all Holders of the Debentures, as
follows:

     SECTION 1. Amendment of Certain Sections of Indenture. Subject to the other
provisions hereof, the Indenture is hereby amended and supplemented in the
following respects:

          (a) Section 13.4 of the Indenture is hereby amended and supplemented
     by adding the following at the end thereof:

          "(k) From and after the effective time of the merger pursuant to the
     Merger Agreement dated as of August 17, 1999, as amended, by and among
     Olsten Corporation, a Delaware corporation ("Olsten"), Gentiva Health
     Services, Inc. (formerly Aaronco Corp.), a Delaware corporation
     ("Gentiva"), Adecco SA, a societe anonyme organized under the laws of
     Switzerland ("Adecco") and Staffing Acquisition Corp., a Delaware
     corporation and a wholly-owned subsidiary of Adecco (the "Merger
     Agreement"), the Holder of each Debenture then outstanding shall have the
     right thereafter, during the period such Debenture shall be convertible as
     specified in Section 13.1, to convert each such Debenture only into (i) the
     number of shares of Gentiva Health Services Common Stock, par value $.10
     per share, and (ii) the amount of (a) Adecco American Depositary Shares
     ("ADSs") or (b) cash or (c) a combination of cash and Adecco ADSs, in each
     case into which such Debenture would have been converted if the Debenture
     was converted into Olsten Class B Stock (as defined in the Merger

<PAGE>
                                      -3-


     Agreement) immediately prior to such merger and as if such holder had made
     a Non-Election (as defined in the Merger Agreement), subject to such
     further adjustments as may be required by the provisions of this
     Indenture."

     SECTION 2. Effect of Supplemental Indenture. Upon the execution and
delivery of this Supplemental Indenture by the Company and the Trustee, the
Indenture and the First Supplemental Indenture shall be supplemented in
accordance herewith, and this Supplemental Indenture shall form a part of the
Indenture for all purposes, and every Holder of Securities heretofore or
hereafter authenticated and delivered under the Indenture shall be bound
thereby.

     SECTION 3. Indenture and First Supplemental Indenture Remains in Full Force
and Effect. Except as supplemented hereby, all provisions in the Indenture and
the First Supplemental Indenture shall remain in full force and effect.

     SECTION 4. Indenture and Supplemental Indenture Construed Together. This
Supplemental Indenture is an indenture supplemental to the Indenture and the
First Supplemental Indenture, and forms a part of the Indenture and the First
Supplemental Indenture for all purposes.

     SECTION 5. Conflict with Trust Indenture Act. If any provision of this
Supplemental Indenture limits, qualifies or conflicts with any provision of
Sections 310 through 317, inclusive, of the Trust Indenture Act, which provision
imposes duties on any Person, the applicable provisions of Sections 310 through
317, inclusive, of the Trust Indenture Act shall control.

     SECTION 6. Separability Clause. In case any provision in this Supplemental
Indenture shall be invalid, illegal or unenforceable, the validity, legality and
enforceability of the remaining provisions shall not in any way be affected or
impaired thereby.

     SECTION 7. Effect of Headings. The Article and Section headings herein are
for convenience only and shall not affect the construction hereof.

     SECTION 8. Benefits of Supplemental Indenture, Etc. Nothing in this
Supplemental Indenture, express or implied, shall give to any Person, other than
the parties hereto and thereto and their successors hereunder, any benefit or
any legal or equitable right, remedy or claim under this Supplemental Indenture.

     SECTION 9. Successors and Assigns. All covenants and agreements in this
Supplemental Indenture by the Company shall bind its successors and assigns,
whether so expressed or not.


<PAGE>
                                      -4-


     SECTION 10. Trustee Not Responsible for Recitals. The recitals contained
herein shall be taken as the statements of the Company, and the Trustee assumes
no responsibility for their correctness. The Trustee makes no representations as
to the validity or sufficiency of this Supplemental Indenture.

     SECTION 11. Certain Duties and Responsibilities of the Trustee. In entering
into this Supplemental Indenture, the Trustee shall be entitled to the benefit
of every provision of the Indenture relating to the conduct or affecting the
liability of or affording protection to the Trustee, whether or not elsewhere
herein so provided.

     SECTION 12. Governing Law. This Supplemental Indenture shall be governed by
and construed in accordance with the laws of the State of New York.

     SECTION 13. Counterparts. This Supplemental Indenture may be executed in
counterparts, each of which, when so executed, shall be deemed to be an
original, but all such counterparts shall together constitute but one and the
same instrument.

     IN WITNESS WHEREOF, the parties hereto have caused this Supplemental
Indenture to be duly executed and attested, all as of the date and year first
above written.

                             QUANTUM HEALTH RESOURCES, INC.


                             By: /s/ John J. Collura
                                 --------------------------------------
                             Title: Senior Vice President


Attest:


/s/ Patricia C. Ma
-----------------------------
Title:  Senior Vice President

                             U.S. BANK TRUST NATIONAL
                             ASSOCIATION, as Trustee


                              By: /s/ Harry H. Hall
                                  --------------------------------------
                              Title: Vice President


Attest:


/s/ Joe Conte
----------------------------
Title:  Asst. Vice President