
<PAGE>   1

                                                                     EXHIBIT 8.1
<TABLE>
<S>                          <C>                             <C>
                                HARWELL HOWARD HYNE
                               GABBERT & MANNER, P.C.
JONATHAN HARWELL                                             JOHN N. POPHAM IV
LIN S. HOWARD                1800 FIRST AMERICAN CENTER      KAAREN H. ENGEL
ERNEST E. HYNE II               315 DEADERICK STREET         SUSAN V. SIDWELL
CRAIG V. GABBERT, JR.        NASHVILLE, TENNESSEE 37238      JOHN F. BLACKWOOD
MARK MANNER                                                  D. ALEXANDER FARDON
JAMES W. CAMERON III          ------------------------       MICHAEL R. HILL
L. GLENN WORLEY                                              JOSEPH ALLEN KELLY
PETER M. OLDHAM               TELEPHONE (615) 256-0500       LAURA A. ROST
GLEN ALLEN CIVITTS            FACSIMILE (615) 251-1059       LEILANI S. SOUTHARD
GLENN B. ROSE                                                D. BRADLEY WALSH
BENJAMIN C. FORDHAM                                          C. MARK PICKRELL
LEE C. DILWORTH                                              CURTIS J. CAPELING
LAUREN W.ANDERSON                                            M. DAVID COX*
                                                              --------    
                                                             *ADMITTED IN TEXAS ONLY
</TABLE>

                                  August 4, 1994



American Transitional Hospitals, Inc.
112 Second Avenue North
Franklin, Tenn 37064

         RE: Merger of ATH Acquisition, Inc. into American
             Transitional Hospitals, Inc.

Gentlemen:

         We have acted as tax counsel to American Transitional Hospitals, Inc.,
a Delaware corporation ("ATH"), in connection with the transactions
contemplated by that certain Agreement and Plan of Merger dated as of June 22,
1994 (the "Agreement") by and among Beverly Enterprises, Inc., a Delaware
corporation ("Beverly"), its wholly-owned subsidiary, ATH Acquisition, Inc., a
Delaware corporation ("Acquisition"), and ATH. Pursuant to the Agreement,
Acquisition will merge with and into ATH and ATH will become a wholly-owned
subsidiary of Beverly (the "Merger").

         In connection with the Merger, you have asked us to render the opinion
described in Section 6(b)(ix) of the Agreement. In response to your request,
our opinion is set forth below. We have also participated in the preparation of
the federal income tax consequences discussion contained in the Form S-4
described below. Subject to the assumptions, qualifications and limitations
contained therein, said discussion fully and fairly addresses the federal
income tax issues material to ATH shareholders in connection with the Merger.
Said discussion, however, should be read in its entirety and does not represent
the opinion of Counsel, which is set forth below. Counsel consents to the
inclusion of a copy of this opinion as an Exhibit to said Form S-4 as filed
with the Securities & Exchange Commission.

         Except as otherwise provided in this letter, capitalized terms
referred to herein have the meanings set forth in the Agreement. All section
references, unless otherwise indicated, are to the Internal Revenue Code of
1986, as amended to the date of this letter (the "Code").
<PAGE>   2
American Transitional Hospitals, Inc.
August 4, 1994
Page 2



         For the purpose of rendering this opinion, we have examined (or will
examine on or prior to the Effective Time of the Merger) and are relying (or
will rely) upon (without any independent investigation or review thereof) the
truth and accuracy, at all relevant times, of the statements, covenants,
representations and warranties contained in the following documents:

                 1.       The Agreement (including Exhibits thereto);

                 2.       Representations made (or to be made) to us by Beverly
         and Acquisition;

                 3.       Representations made (or to be made) to us by ATH;

                 4.       Representations made (or to be made) to us in
         Continuity of Interest Certificates by certain shareholders of ATH;

                 5.       The Form S-4 filed by Beverly with the Securities and
         Exchange Commission pursuant to the Securities Act of 1933, as
         amended;

                 6.       Such other instruments and documents relating to the
         formation, organization and operation of Beverly, Acquisition and ATH
         or to the consummation of the Merger and the transactions contemplated
         in the Agreement as we have deemed necessary or appropriate.

         In connection with rendering this opinion, we have assumed or obtained
(or will obtain) representations (and are relying thereon, without any
independent investigation or review thereof) that:

                 1.       Original documents (including signatures) are
         authentic; documents submitted to us as copies conform to the original
         documents; and there has been (or will be by the Effective Time of the
         Merger) due execution and delivery of all documents where due
         execution and delivery are prerequisites to effectiveness thereof.

                 2.       The transactions contemplated by the Agreement and
         the Form S-4 will be consummated as described therein.

                 3.       ATH, Beverly and Acquisition have the legal right and
         power under all applicable laws and regulations to enter into, execute
         and consummate the transactions contemplated by and described in the
         Agreement and the Form S-4.
<PAGE>   3
American Transitional Hospitals, Inc.
August 4, 1994
Page 3



                 4.       The continuity of interest requirement as specified
         in U.S. Treasury Regulation Section 1.368-1(b) and as interpreted in
         certain Internal Revenue Service rulings and federal judicial
         decisions will be satisfied.

                 5.       After the Merger, ATH will hold "substantially all"
         of the properties held prior to the Merger by it and Acquisition
         within the meaning of Section 368(a)(2)(E)(i) of the Code and the
         Treasury Regulations promulgated thereunder.

                 6.       To the extent any expenses relating to the Merger (or
         the "plan of reorganization" within the meaning of Treasury Regulation
         Sections 1.368-1(c) and 1.368-2(g) with respect to the Merger) are
         funded directly or indirectly by a party other than the incurring
         party, such expenses will be within the guidelines established in
         Revenue Ruling 73-54, 1973-1 C.B. 1987.

                 7.       No outstanding indebtedness of ATH, Beverly or
         Acquisition has or will represent equity for tax purposes; no
         outstanding equity of ATH, Beverly or Acquisition has represented or
         will represent indebtedness for tax purposes; no outstanding security,
         instrument, agreement or arrangement (other than ATH common or
         preferred stock) that provided for or contains a right to acquire ATH
         common or preferred stock or to share in the appreciation of ATH
         common or preferred stock will represent outstanding equity of ATH for
         purposes of Section 368(c) of the Code.

                 8.       Any representation or statement made "to the best of
         knowledge" or similarly qualified is correct without such
         qualification.

         Based on our examination of the foregoing items and subject to the
assumptions, exceptions, limitations and qualifications set forth herein, we
are of the opinion that, for federal income tax purposes, the Merger will
constitute a "reorganization" as defined in Section 368(a) of the Code.

         In addition to the assumptions set forth above, this opinion is
subject to the exceptions, limitations and qualifications set forth below.

                 1.       This opinion is rendered as of the date of this
         letter and represents, and is based upon our best judgment, regarding
         the application of federal income tax laws arising under the Code,
         existing judicial decisions, administrative
<PAGE>   4
American Transitional Hospitals, Inc.
August 4, 1994
Page 4



         regulations and published rulings and procedures. our opinion is not
         binding upon the Internal Revenue Service or the courts, and the
         Internal Revenue Service is not precluded from successfully asserting
         a contrary position. Furthermore, no assurance can be given that
         future legislative, judicial or administrative changes, on either a
         prospective or retroactive basis, would not adversely affect the
         accuracy of the conclusions stated herein. Nevertheless, we undertake
         no responsibility to advise you of any new developments in the
         application or interpretation of the federal income tax laws.

                 2.       No opinion is expressed as to the tax consequences of
         the issuance by Beverly of its common stock or the receipt by ATH
         preferred shareholders of such Beverly common stock in exchange for
         accumulated but undeclared dividends relating to the ATH preferred
         stock exchanged therefor.

                 3.       This opinion addresses only the specific tax opinion
         set forth above, and does not address any other federal, state, local
         or foreign tax consequences that may result from the Merger or any
         other transaction (including any transaction undertaken in connection
         with the Merger). In particular, without limitation, we express no
         opinion regarding (i) whether, and the extent to which, any ATH
         shareholder who has provided or will provide services to ATH, Beverly
         or Acquisition will have compensation income under any provision of
         the Code; (ii) the effects of any such compensation income, including
         but not limited to, the effect upon the basis and holding period of
         the Beverly common stock received by any such shareholder in the
         Merger; (iii) the potential application of the "golden parachute"
         provisions (Sections 280G, 3121(v) (2) and 4999) of the Code, the
         alternative minimum tax provisions (Sections 55, 56, and 57) of the
         Code and Sections 108, 305, 306, 357 and 424 of the Code, or the
         Treasury Regulations promulgated thereunder; (iv) the tax consequences
         of the Merger to Beverly, Acquisition or ATH, including without
         limitation, the recognition of any gain and the survival and/or
         availability, after the Merger, of any of the federal income tax
         attributes or elections of ATH, after application of any provision of
         the Code, as well as the Treasury Regulations promulgated thereunder
         and judicial interpretations thereof; (v) the basis of any equity
         interest in ATH acquired by Beverly in the Merger; (vi) the tax
         consequences of any transaction in which ATH stock or a right to
         acquire ATH stock was received; and (vii) the tax consequences of the
         Merger (including the opinion set forth
<PAGE>   5
American Transitional Hospitals, Inc.
August 4, 1994
Page 5



         above) as applied to specific stockholders of ATH and/or holders of
         options or warrants for ATH stock, including but not limited to,
         dealers in securities, corporate shareholders subject to the
         alternative minimum tax, foreign persons, and holders of shares
         acquired upon exercise of stock options or in other compensatory
         transactions, including without limitation the tax consequences to the
         holders of options for ATH stock of Beverly's assumption of such
         outstanding options.

                 4.       No opinion is expressed as to any transaction other
         than the Merger as described in the Agreement or to any transaction
         whatsoever, including the Merger, if all the transactions described in
         the Agreement are not consummated in accordance with the terms of such
         Agreement and without waiver or breach of any material provision
         thereof or if all of the representations, warranties, statements and
         assumptions upon which we have relied are not true and accurate at all
         relevant times. In the event any one of the statements,
         representations, warranties, or assumptions upon which we have relied
         to issue this opinion is incorrect, our opinion might be adversely
         affected and may not be relied upon.

                 5.       This opinion is intended solely for the purpose of
         satisfying the requirements of Section 6(b)(ix) of the Agreement, and
         accordingly, may not be relied upon for any other purpose or by any
         other person or entity, and may not be made available to any other
         person or entity without our prior written consent.

                                           Sincerely,


                                           HARWELL HOWARD HYNE GABBERT
                                           & MANNER, P.C.

                                           /s/ HARWELL HOWARD HYNE GABBERT
                                           & MANNER, P.C.
