Exhibit (d)(12)

[REXALL LOGO]                                    6111 Broken Sound Parkway NW
                                                 Boca Raton, FL 88487
                                                 (662) 341-8400
                                                 Fax (561) 999-4716

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                                       March 22, 2000


VIA FACSIMILE


Koninklijke (Royal) Numico N.V.
P.O. Box 1
2700 MA Zoetermeer
The Netherlands
Attn: Johannes C.T. van der Wielen
      President and Chief Executive Officer


                           CONFIDENTIALITY AGREEMENT


Dear Hans:

In connection with your possible interest in the purchase of all of the
outstanding shares for cash (the "Transaction") of Rexall Sundown, Inc. (the
"Company"), you have requested that we or our representatives furnish you or
your representatives with certain information relating to the Company or the
Transaction. All such information (whether written or oral) furnished
(whether before or after the date hereof) by us or our directors, officers,
employees, affiliates, representatives (including, without limitation,
financial advisors, attorneys and accountants) or agents (collectively, "our
Representatives") to you or your directors, officers, employees, affiliates,
representatives (including, without limitation, financial advisors, attorneys
and accountants) or agents or your potential sources of financing for the
Transaction (collectively, "your Representatives") and all analyses,
compilations, forecasts, studies or other documents prepared by you or your
Representatives in connection with your or their review of, or your interest
in, the Transaction which contain or reflect any such information is
hereinafter referred to as the "Information". The term Information will not,
however, include information which (i) is or becomes publicly available other
than as a result of a disclosure by you or your Representatives or (ii) is or
becomes available to you on a nonconfidential basis from a source



Koninklijke (Royal) Numico N.V.
March 22, 2000
Page 2

(other than us or our Representatives) which, to the best of your knowledge,
is not prohibited from disclosing such information to you by a legal,
contractual or fiduciary obligation to us.

Accordingly, you hereby agree that:

1.   You and your Representatives (i) will keep the Information confidential
     and will not (except as required by applicable law, regulation or legal
     process, and only after compliance with paragraph 3 below), without our
     prior written consent, disclose any Information in any manner whatsoever,
     and (ii) will not use any Information other than in connection with the
     Transaction; PROVIDED, HOWEVER, that you may reveal the Information to
     your Representatives (a) who need to know the Information for the purpose
     of evaluating the Transaction, (b) who are informed by you of the
     confidential nature of the Information and (c) who agree to act in
     accordance with the terms of this letter agreement. You will cause your
     Representatives to observe the terms of this letter agreement, and you
     will be responsible for any breach of this letter agreement by any of your
     Representatives.

2.   You and your Representatives will not (except as required by applicable
     law, regulation or legal process, and only after compliance with
     paragraph 3 below), without our prior written consent, disclose to any
     person the fact that the Information exists or has been made available,
     that you are considering the Transaction or any other transaction
     involving the Company, or that discussions or negotiations are taking or
     have taken place concerning the Transaction or involving the Company or
     any term, condition or other fact relating to the Transaction or such
     discussions or negotiations, including, without limitation, the status
     thereof.

3.   In the event that you or any of your Representatives are requested
     pursuant to, or required by, applicable law, regulation or legal process
     to disclose any of the Information, you will notify us promptly so that
     we may seek a protective order or other appropriate remedy or, in our sole
     discretion, waive compliance with the terms of this letter agreement. In
     the event that no such protective order or other remedy is obtained, or
     that the Company does not waive compliance with the terms of this letter
     agreement, you will furnish only that portion of the Information which you
     are advised by counsel is legally required and will exercise all
     reasonable efforts to obtain reliable assurance, where permitted by law,
     that confidential treatment will be accorded the Information.

4.   If you determine not to proceed with the Transaction, you will promptly
     inform the Company or Morgan Stanley & Co. Incorporated ("Morgan
     Stanley") of that decision and in that case, and at any time upon the
     request of the Company or any of our Representatives, you will promptly
     deliver to the Company at your own expense all copies of the written
     Information in your or your Representatives' possession; PROVIDED,
     HOWEVER, all analyses, compilations, forecasts, studies or other documents
     prepared by you or your Representatives shall, in lieu of being returned,
     be destroyed, and such




Koninklijke (Royal) Numico N.V.
March 22, 2000
Page 3


     destruction shall be certified to the Company. Any oral Information will
     continue to be subject to the terms of this letter agreement.

5.   You acknowledge that none of us, Morgan Stanley or its affiliates, our
     other Representatives, or any of our or their respective officers,
     directors, employees, agents or controlling persons within the meaning
     of Section 20 of the Securities Exchange Act of 1934, as amended, makes
     any express or implied representation or warranty as to the accuracy or
     completeness of the Information, and you agree that no such person will
     have any liability relating to the Information or for any errors therein
     or omissions therefrom. You further agree that you are not entitled to
     rely on the accuracy or completeness of the Information and that you will
     be entitled to rely solely on such representations and warranties as may
     be included in any definitive agreement with respect to the Transaction,
     subject to such limitations and restrictions as may be contained therein.

6.   You are aware, and you will advise your Representatives who are informed
     of the matters that are the subject of this letter agreement, of the
     restrictions imposed by the United States securities laws on the
     purchase or sale of securities by any person who has received material,
     non-public information from the issuer of such securities and on the
     communication of such information to any other person when it is
     reasonably foreseeable that such other person is likely to purchase or
     sell such securities in reliance upon such information.

7.   You agree that, for a period of eighteen (18) months from the date of
     this letter agreement, neither you nor any of your affiliates will,
     without the prior written consent of the Company or its Board of
     Directors: (i) acquire, offer to acquire, or agree to acquire, directly
     or indirectly, by purchase or otherwise, any voting securities or direct
     or indirect rights to acquire any voting securities of the Company or
     any subsidiary thereof, or of any successor to or person in control of
     the Company, or any material assets of the Company or any subsidiary or
     division thereof or of any such successor or controlling person; (ii)
     make, or in any way participate in, directly or indirectly, any
     "solicitation" of "proxies" (as such terms are used in the rules of the
     Securities Exchange Commission) to vote, or seek to advise or influence
     any person or entity with respect to the voting of, any voting
     securities of the Company; (iii) make any public announcement with
     respect to, or submit a proposal for, or offer of (with or without
     conditions) any extraordinary transaction involving the Company or its
     securities or assets; (iv) form, join or in any way participate in a
     "group" (as defined in Section 13 (d)(3) of the Securities Exchange Act
     of 1934, as amended) in connection with any of the foregoing; or (v)
     publicly request the Company or any of our Representatives, directly or
     indirectly, to amend or waive any provision of this paragraph; PROVIDED,
     HOWEVER, that the obligations set forth in this paragraph and in
     paragraph 2 of this Agreement shall terminate immediately upon the
     Company entering into or announcing a definitive agreement with a third
     party providing that (a) a merger pursuant to which the Company would
     cease to be a publicly-held company, (b) the acquisition of more than
     fifty percent (50%) of the common stock of the



Koninklijke (Royal) Numico N.V.
March 22, 2000
Page 4


     Company, or (c) a sale of all or substantially all of the assets of the
     Company. You will promptly advise the Company of any inquiry or proposal
     made to you with respect to any of the foregoing.

8.   You agree that, for a period of two (2) years from the date of this
     letter agreement, you will not, directly or indirectly, solicit for
     employment or hire any executive employee of the Company or any of its
     subsidiaries; PROVIDED, HOWEVER, that the foregoing provision will not
     prevent you from employing any such person who contacts you on his or her
     own initiative without any direct or indirect solicitation by or
     encouragement from you.

9.   You acknowledge and agree that (a) we and our Representatives are free
     to conduct the process leading up to a possible Transaction as we and
     our Representatives, in our sole discretion, determine (including,
     without limitation, by negotiating with any prospective buyer and
     entering into a preliminary or definitive agreement without prior notice
     to you or any other person), (b) we reserve the right, in our sole
     discretion, to change the procedures relating to our consideration of
     the Transaction at any time without prior notice to you or any other
     person, to reject any and all proposals made by you or any of your
     Representatives with regard to the Transaction, and to terminate
     discussions and negotiations with you at any time and for any reason,
     and (c) unless and until a written definitive agreement concerning the
     Transaction has been executed, neither we nor any of our Representatives
     will have any liability to you with respect to the Transaction, whether
     by virtue of this letter agreement, any other written or oral expression
     with respect to the Transaction or otherwise; PROVIDED, HOWEVER, if we
     decide not to proceed with the Transaction we will promptly inform you
     of that decision.

10.  You acknowledge that remedies at law may be inadequate to protect us
     against any actual or threatened breach of this letter agreement by you
     or by your Representatives, and, without prejudice to any other rights
     and remedies otherwise available to us, you agree the Company may seek
     the granting of injunctive relief in our favor without proof of actual
     damages. In the event of litigation relating to this letter agreement,
     if a court of competent jurisdiction determines in a final,
     nonappealable order that this letter agreement has been breached by you
     or by your Representatives, then you will reimburse the Company for its
     costs and expenses (including, without limitation, legal fees and
     expenses) incurred in connection with all such litigation; provided,
     however, if a court of competent jurisdiction determines in a final
     nonappealable order that this letter agreement has not been breached by
     you or by your Representatives, then we will reimburse you for your costs
     and expenses (including, without limitation, legal fees and expenses)
     incurred in connection with all such litigation.

11.  You agree that no failure or delay by us in exercising any right, power or
     privilege hereunder will operate as a waiver thereof, nor will any single
     or partial exercise thereof




Koninklijke (Royal) Numico N.V.
March 22, 2000
Page 5


     preclude any other or further exercise thereof or the exercise of any
     right, power or privilege hereunder.

12.  This letter agreement will be governed by and construed in accordance
     with the laws of the State of Florida applicable to contracts between
     residents of that State and executed in and to be performed in that
     State.

13.  This letter agreement contains the entire agreement between you and us
     concerning the confidentiality of the Information, and no modifications
     of this letter agreement or waiver of the terms and conditions hereof will
     be binding upon you or us, unless approved in writing by each of you and
     us.

14.  This Agreement shall terminate and have no further effect upon the fifth
     anniversary hereof.

Please confirm your agreement with the foregoing by signing and returning to
the undersigned the duplicate copy of this letter enclosed herewith.


                                       Very truly yours,

                                       REXALL SUNDOWN, INC.

                                       By: /s/ Geary Cotton
                                           ------------------------------

                                       Name: Geary Cotton

                                       Title: Chief Financial Officer

Accepted and Agreed as of the date
first written above:


KONINKLIJKE (ROYAL) NUMICO N.V.

By: /s/ J.C.T. van der Wielen
    ----------------------------

Name: J.C.T. van der Wielen
      --------------------------

Title: President and CEO
       -------------------------