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                                                                     Exhibit 5.1

                       [Letterhead of Goodwin Procter LLP]


November 7, 2002


Inverness Medical Innovations, Inc.
51 Sawyer Road, Suite 200
Waltham, MA 02453

Re:  REGISTRATION STATEMENT ON FORM S-4

Ladies and Gentlemen:

In accordance with Item 601(b)(5) of Regulation S-K, we are furnishing this
opinion to you in our capacity as counsel to Inverness Medical Innovations, Inc.
(the "Company") in connection with the preparation of a registration statement
on Form S-4 (the "Registration Statement"), to be filed with the Securities and
Exchange Commission under the Securities Act of 1933, as amended (the
"Securities Act"), on or about the date hereof. The Registration Statement
relates to up to 2,300,511 shares (the "Shares") of the Company's common stock,
par value $.001 per share (the "Common Stock"), to be issued to the shareholders
of Ostex International, Inc. ("Ostex") in connection with the merger of Geras
Acquisition Corp. ("Geras"), a Washington corporation and wholly owned
subsidiary of the Company, with and into Ostex. We understand the Shares are to
be offered and sold in the manner described in the Registration Statement.

As counsel for the Company, we have examined copies of the following documents:
(i) the Registration Statement and the exhibits thereto; (ii) the Agreement and
Plan of Merger, dated as of September 6, 2002, by and between the Company, Geras
and Ostex (the "Agreement"); (iii) the Company's Certificate of Incorporation
and By-laws, each as amended to date and presently in effect; (iv) such records
of the corporate proceedings of the Company as we deemed material; and (v) such
records, certificates and other documents of the Company as we have deemed
necessary or appropriate for the purposes of this opinion. In our examination,
we have assumed the genuineness of all signatures, the legal capacity of natural
persons, the authenticity of all documents submitted to us as certified,
photostatic or facsimile copies, the authenticity of the originals of such
copies and the authenticity of telephonic confirmations of public officials and
others. As to facts material to our opinion, we have relied upon certificates or
telephonic confirmations of public officials and certificates, documents,
statements and other information of the Company or representatives or officers
thereof.

We are attorneys admitted to practice in The Commonwealth of Massachusetts. We
express no opinion concerning the laws of any jurisdictions other than the
federal laws of the United States of America, The Commonwealth of Massachusetts
and the Delaware General Corporation Law

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Inverness Medical Innovations, Inc.
November 7, 2002
Page 2


(which includes applicable provisions of the Delaware Constitution and reported
judicial decisions interpreting the Delaware General Corporation Law and the
Delaware Constitution).

Based on the foregoing, we are of the opinion that the Shares have been duly
authorized and, when the Registration Statement relating to the Shares is
declared effective under the Securities Act and the Shares have been issued in
exchange for the shares of common stock of Ostex as contemplated in the
Agreement, the Shares will be validly issued, fully paid and non-assessable by
the Company.

This opinion shall be interpreted in accordance with the Legal Opinion
Principles issued by the Committee on Legal Opinions of the American Bar
Association's Business Law Section as published in 53 Business Lawyer 831 (May
1998).

The opinions expressed herein are being furnished to you solely for your benefit
in connection with the Registration Statement, and may not be used or relied
upon by you for any other purpose. This opinion is given as of the date first
set forth above, and we assume no obligation to update this opinion after the
date hereof. We hereby consent to the inclusion of this opinion as an exhibit to
the Registration Statement and to the reference to our firm under the heading
"Legal Matters" in the Company's proxy statement/prospectus which is part of the
Registration Statement.

Very truly yours,

/s/ Goodwin Procter LLP

GOODWIN PROCTER LLP