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                                                                     Exhibit 5.1

                                      November 15, 2000

PolyMedica Corporation
11 State Street
Woburn, MA 01801

     Re:  Registration Statement on Form S-3
          ----------------------------------

Ladies and Gentlemen:

     This opinion is furnished to you in connection with a Registration
Statement on Form S-3 (File No. 333-35312) (the "Registration Statement") filed
by PolyMedica Corporation, a Massachusetts corporation (the "Company"), with the
Securities and Exchange Commission (the "Commission") under the Securities Act
of 1933, as amended (the "Securities Act"), for the registration of the
Company's common stock, $0.01 par value per share (the "Shares"), all of which
may be issued from time to time on a delayed or continuous basis pursuant to
Rule 415 under the Securities Act at an aggregate initial offering price not to
exceed $100,000,000.



     We are acting as counsel for the Company in connection with the sale by the
Company of the Shares. We have examined signed copies of the Registration
Statement as filed with the Commission. We have also examined and relied upon
minutes of meetings of the stockholders and the Board of Directors of the
Company as provided to us by the Company, stock record books of the Company as
provided to us by the Company, the Certificate of Incorporation and By-Laws of
the Company, each as restated and/or amended to date, and such other documents
as we have deemed necessary for purposes of rendering the opinions hereinafter
set forth.


     In our examination of the foregoing documents, we have assumed the
genuineness of all signatures, the authenticity of all documents submitted to us
as originals, the conformity to original documents of all documents submitted to
us as copies, the authenticity of the originals of such latter documents and the
legal competence of all signatories to such documents.

     We assume that the appropriate action will be taken, prior to the offer and
sale of the Shares, to register and qualify the Shares for sale under all
applicable state securities or "blue sky" laws.


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PolyMedica Corporation
November 15, 2000
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     We express no opinion herein as to the laws of any state or jurisdiction
other than the state laws of the Commonwealth of Massachusetts, the General
Corporation Law of the State of Delaware and the federal laws of the United
States of America.

     Based upon and subject to the foregoing, we are of the opinion that when
(i) the Shares have been specifically authorized for issuance by the Company's
Board of Directors or an authorized committee thereof (the "Authorizing Votes"),
(ii) the Registration Statement has become effective under the Securities Act,
(iii) the terms of the sale of the Shares have been duly established in
conformity with the Company's Restated Articles of Organization and By-laws and
do not violate any applicable law or result in a default under or breach of any
agreement or instrument binding on the Company and comply with any requirement
or restriction imposed by any court or governmental body having jurisdiction
over the Company, (iv) the Shares have been issued and sold as contemplated by
the Registration Statement, and (v) the Company has received the consideration
provided for in the Authorizing Votes, the Shares will be validly issued, fully
paid and nonassessable.




     It is understood that this opinion is to be used only in connection with
the offer and sale of the Shares while the Registration Statement is in effect.

     Please note that we are opining only as to the matters expressly set forth
herein, and no opinion should be inferred as to any other matters. This opinion
is based upon currently existing statutes, rules, regulations and judicial
decisions, and we disclaim any obligation to advise you of any change in any of
these sources of law or subsequent legal or factual developments which might
affect any matters or opinions set forth herein.

     We hereby consent to the filing of this opinion with the Commission as an
exhibit to the Registration Statement in accordance with the requirements of
Item 601(b)(5) of Regulation S-K under the Securities Act and to the use of our
name therein and in the related Prospectus. In


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PolyMedica Corporation
November 15, 2000
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giving such consent, we do not hereby admit that we are in the category of
persons whose consent is required under Section 7 of the Securities Act or the
rules and regulations of the Commission.


                                             Very truly yours,


                                             /s/ HALE AND DORR LLP


                                             HALE AND DORR LLP