<PAGE>

                                                                     EXHIBIT 4.4

     SECOND AMENDMENT TO RIGHTS AGREEMENT (this "Amendment") dated as of
September 21, 2001, between IVC INDUSTRIES, INC., a Delaware corporation (the
"Corporation"), and AMERICAN STOCK TRANSFER & TRUST COMPANY (the "Rights
Agent"). Capitalized terms used but not defined in this Amendment shall have the
respective meanings attributed to such terms in the Rights Agreement dated as of
May 15, 2001, and as amended by the First Amendment dated as of February 1, 2001
between the parties (the "Rights Agreement").

                              W I T N E S S E T H :
                              - - - - - - - - - -

     WHEREAS, the parties acknowledge that the Rights Agreement is in full force
and effect; and

     WHEREAS, the parties deem it necessary or desirable to amend the Rights
Agreement as hereinafter provided.

     NOW, THEREFORE, the parties hereto agree as follows:

     1. Section 1(k) of the Rights Agreement is hereby deleted in its entirety
and the following new Section 1(k) is inserted in lieu thereof:

     "(b) "Exempt Stockholder" shall mean at any time (i) any Person who or
which, together with all Affiliates and Associates of such Person (which for the
purpose of this definition shall exclude any Company Related Entity), as of the
close of business on the day the Corporation publicly announces that the Board
of Directors has adopted

<PAGE>

this Agreement (the "Announcement Date"), was the Beneficial Owner of more than
15 percent of the shares of Common Stock, (ii) any member of the Edell Family,
(iii) Andrew Pinkowski, and (iv) Inverness Medical Innovations, Inc., and its
Affiliates and Associates ("Inverness") solely to the extent that Inverness may
be deemed to be a Beneficial Owner as a result of its right to vote and exercise
related rights with respect to the Company's capital stock pursuant to the
certain stockholder voting agreements and irrevocable proxies made and entered
into as of September 21, 2001 by and between Inverness and each of E. Joseph
Edell, Beverly Edell, the Edell Family Partnership, and Ethel Edell, as
Executrix for the Estate of Arthur Edell; provided, however, that any such
Person, together with all Affiliates and Associates of such Person, shall not be
an Exempt Stockholder if the number of shares of Common Stock Beneficially Owned
by that Person, together with all Affiliates and Associates of such Person
(other than as a result of a stock dividend, stock split or stock distribution
by the Corporation), exceeds by more than one percent the number of shares of
Common Stock Beneficially Owned by that Person, together with all Affiliates and
Associates of such Person, as of the Announcement Date. Notwithstanding any
provision herein in to the contrary, E. Joseph Edell is authorized to acquire up
to 200,000 additional shares of Common Stock, and that the acquisition of such
shares shall not result in E. Joseph Edell being deemed an Acquiring Person."

     2. This Amendment was authorized by the Corporation's Board of Directors at
a meeting held on September 21, 2001.

<PAGE>

     3. Except as specifically amended hereby, the Rights Agreement shall remain
unaffected by this Amendment, and the remaining terms of the Rights Agreement
are hereby reconfirmed.

     4. This Amendment may be executed in counterparts, each of which shall be
deemed an original but all of which together shall constitute one and the same
instrument.

     IN WITNESS WHEREOF, the parties have executed this Amendment as of the day
and year first above written.

                                        IVC INDUSTRIES, INC.
     Attest:

     By: /s/ Vita S. Ricci              By: /s/ E. Joseph Edell
        --------------------------         ---------------------------------
     Name:   Vita S. Ricci              Name:  E. Joseph Edell
     Title:  Executive Assistant       Title: Chief Executive Officer

                                        AMERICAN STOCK TRANSFER & TRUST COMPANY

     Attest:

     By: /s/ Wilbert Myles              By: /s/ Herbert J. Lemmer
        --------------------------         ---------------------------------
     Name:   Wilbert Myles              Name:  Herbert J. Lemmer
     Title:  Vice President             Title: Vice President