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                       FIRST AMENDMENT TO RIGHTS AGREEMENT

     THIS FIRST AMENDMENT TO RIGHTS AGREEMENT (the  "Amendment") is entered into
as of August 1, 2005 by PolyMedica  Corporation,  a Massachusetts  corporation
(the  "Company"),  and  EquiServe  Trust  Company,  as Rights Agent (the "Rights
Agent"),  with respect to the Rights  Agreement dated September 13, 2002 between
the Company and the Rights Agent.

     WHEREAS,  on September  12, 2002 the Board of Directors of the Company (the
"Board")  authorized and declared a dividend  distribution of one Right for each
share of Common  Stock (as  defined  in the  Rights  Agreement)  of the  Company
outstanding at the close of business on September 24, 2002 (the "Record  Date"),
and  authorized  the issuance of one Right for each share of Common Stock of the
Company issued between the Record Date (whether  originally  issued or delivered
from the  Company's  treasury) and the earlier of the  Distribution  Date or the
Expiration  Date,  each Right initially  representing  the right to purchase one
one-thousandth  of a share of Series B Junior  Participating  Preferred Stock of
the  Company  having  the  rights,  powers  and  preferences  set  forth  in the
Certificate  of  Vote  filed  with  the  Secretary  of the  Commonwealth  of the
Commonwealth of Massachusetts,  upon the terms and subject to the conditions set
forth in the Rights Agreement (the "Rights");

     WHEREAS,  no  Distribution  Date,  as defined in Section 3(a) of the Rights
Agreement,  or Stock Acquisition Date, as defined in Section 1(ii) of the Rights
Agreement, has occurred, and the Rights are currently redeemable;

     WHEREAS,  Section 27 of the Rights Agreement  provides that, so long as the
Rights are redeemable,  the Company may, and the Rights Agent shall (if directed
by the Company), supplement or amend the Rights Agreement in any respect without
the approval of any holders of Rights;

     WHEREAS, the Company intends to modify the terms of the Rights Agreement as
set forth herein, and in connection  therewith,  is entering into this Amendment
and directing the Rights Agent to enter into this Amendment;

     WHEREAS,  the Board of Directors of the Company has approved this Amendment
and authorized its  appropriate  officers to execute and deliver the same to the
Rights Agent, and has directed the Rights Agent to execute this Amendment;

     NOW, THEREFORE,  in consideration of the premises and the mutual agreements
herein set forth, the parties hereby agree as follows:

     Section 1(s) of the Rights  Agreement is hereby amended and restated in its
entirety to read as follows:

     "`Final  Expiration  Date' shall mean the close of business on August 10,
2005."


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     IN WITNESS WHEREOF,  the parties have duly executed this First Amendment to
Rights Agreement as of the date first written above.



                                        POLYMEDICA CORPORATION

                                        By: /s/ Devin J. Anderson
                                            --------------------------------
                                        Name: Devin J. Anderson
                                              ------------------------------
                                        Title: General Counsel & Secretary
                                               -----------------------------

                                        EQUISERVE TRUST COMPANY, AS RIGHTS
                                        AGENT

                                        By: /s/ Katherine Anderson
                                            --------------------------------
                                        Name: Katherine Anderson
                                              ------------------------------
                                        Title: Managing Director
                                               -----------------------------