<PAGE>   1
                     U.S. SECURITIES & EXCHANGE COMMISSION

                             WASHINGTON, D.C. 20549

                                  FORM 10-QSB

( X ) Amended Quarterly report under Section 13 or 15(d) of the Securities
Exchange Act of 1934 for the quarter period of March 31, 1997.

(   ) Transition report under Section 13 or 15(d) of the Securities Exchange
Act of 1934 for the transition period from              to              .

                         Commission File Number 0-9185

                            MEDCO HEALTH CORPORATION
                      (Formerly Williston Oil Corporation)

Nevada                                                             22-1934084
(State or other jurisdiction of           (IRS Employer Identification Number)
incorporation or organization)

532 Sylvan Avenue
Englewood Cliffs, New Jersey                                            07632
(address of Principal Executive Offices)                           (Zip Code)

                                 (201)541-8444
              (Registrant's telephone number, including area code)

         Securities registered under Section 12(b) of the Exchange Act:

                                      None

         Securities registered under Section 12(g) of the Exchange Act:

                     Class A Common Stock, $.001 Par Value

     Check whether the issuer (1) filed all reports required to be filed by
Section 13 or 15(d) of the Exchange Act during the preceding twelve (12) months
(or for such shorter period that registrant was required to file such
reports), and (2) has been subject to such filing requirements for the past
ninety (90) days. YES ( X )(   ).

                      Applicable Only to Corporate Issuers

     State the number of shares outstanding of each of the issuer's classes of
     common equity:

     36,695,543 Shares of Class A Common Stock, $.001 par value
      1,250,000 Shares of Class B Common Stock, $.001 par value  

                 Transitional Small Business Disclosure Format

                               YES ( X ) NO ( X )
<PAGE>   2
Item 1. Financial Statements

     The financial statements of the Company, required to be included in this
report pursuant to Item 310(a) of Regulation S-13, are set forth below:

<PAGE>   3
                Medco Health Corporation (formerly Medco, Inc.)
                         (A Development Stage Company)
                                        
                                        
                            Statements of Operations


<TABLE>
<CAPTION>
                                                                                                                 Cumulative
                                                       Three months                   Nine months               Period from
                                                          ended                         ended                  July 1, 1994
                                                         March 31,                    March 31,                 (Date of
                                                -----------------------------   --------------------------     Inception) to
                                                   1996           1997            1996            1997         March 31, 1997 
                                                -------------    ------------    ----------      ----------    ---------------

<S>                                             <C>             <C>             <C>             <C>             <C>
Revenues                                        $    458        $      --       $  3,857        $      --       $  83,069

Cost of sales                                      3,961               --          5,462               --          16,939
                                                ---------       ----------      ---------       ----------      ----------

Gross profit                                      (3,503)              --         (1,605)              --          66,130
                                                ---------       ----------      ---------       ----------      ----------

General and administrative expenses:
  Payroll -- officers                              1,000               --          1,000          32,390           39,890
  Payroll -- other                                 1,050               --          1,050           8,000           23,689
  Taxes and licenses                                  68            4,620            314           8,702           11,002
  Management fees                                     --            9,196             --          13,111           19,036
  Commission expense                               3,680           28,685         17,551          28,885           37,285
  Travel                                           3,969               --          3,969             450            7,324
  Miscellaneous                                       --              299            750           2,294            3,044
  Bad debt                                            --              --              --              --           60,746
  Insurance                                        1,298            7,064          1,903          15,233           20,521

  Supplies                                            --            3,310            230           5,780            5,780
  Advertising                                        401               --            797              --            1,844
  Truck and auto expenses                             56              561            461           1,430            4,932
  Rent                                             3,000           32,000          6,000          43,000           54,075
  Telephone                                        1,317            3,353          2,896           3,959           10,772
  Utilities                                        1,072              524          1,486             958            3,083
  Repairs and maintenance                             68               --            206              35              987
  Office expense                                     136              367            633             588            2,256
  Seminars                                            --               --             68              --              648
  Professional fees                                   --           41,100          1,000          45,145           52,818
  Depreciation and amortization                    2,627            2,650          7,881           7,950           21,784
                                                ---------       ----------      ---------       ---------       ----------
                                                  19,742          133,729         48,150         217,910          381,516
                                                ---------       ----------      ---------       ---------       ----------
</TABLE>


                       See Notes to Financial Statements
<PAGE>   4
                Medco Health Corporation (formerly Medco, Inc.)
                         (A Development Stage Company)
                                        
                                        
                            Statements of Operations


<TABLE>
<CAPTION>

<S>                                             <C>             <C>             <C>             <C>             <C>
Operating loss                                   (23,245)        (133,729)       (49,755)        (217,910)       (315,386)

Gain (loss) on equipment                              --               --             --           59,800          26,172
                                                ---------       ---------       ---------       ----------      ----------

Loss before provision for income taxes           (23,245)        (133,729)       (49,755)        (158,110)       (289,214)

Provision for income taxes                            --               --             --               --             827
                                                --------        ----------      ---------       ----------      ----------

Net loss                                        $(23,245)       $(133,729)      $(49,755)       $(158,110)      $(290,041)
                                                =========       ==========      =========       ==========      ==========

Net loss per common share                       $     --        $      --       $     --        $      --       $      --
                                                ========        =========       =========       ==========      ==========
</TABLE>


                       See Notes to Financial Statements
<PAGE>   5
                Item 2. Management's Discussion and Analysis of
                  Financial Condition and Result of Operations

        The following is management's discussion and analysis of significant
factors which have affected the Registrant's financial position and operations
during the fiscal quarter that ended March 31, 1997. 

                        Liquidity and Capital Resources

        The activities of the registrant since its reorganization on January
16, 1996 have been financed by various loans.

        The company currently owns three vehicles, a Land Cruiser, a BMW, and a
Dodge Colt. The company will also own the laboratory, including all of its
furnishings, once it is complete.

        The company currently has a negative net worth. There is no assurance
that the company will, in fact, be able to raise adequate funding and actually
expand its operations as contemplated, or even to bring its present operations
to a profitable level.

                             Results of Operations

        The company's revenues from its date of inception until March 31, 1997
is $83,069.00. The company has no revenue for the three months that ended March
31, 1997.

        The management of the company has continued to devote the company's
resources to the completion of the clinical laboratory in Engelwood Cliffs, New
Jersey.

                    Item 6. Exhibits and Reports on Form S-K

        (a) Exhibits filed herewith:

        None

        (b) Current reports on Form 10KSB; dated April 17, 1997, filed with the
Securities and Exchange Commission.
<PAGE>   6
                                   SIGNATURES

        In accordance with the requirements of the Exchange Act, the registrant
caused this report to be signed on its behalf by the undersigned thereunto duly
authorized.

                                        MEDCO HEALTH CORPORATION




                                        By: /s/ FAHIM SAHRAIE       
                                           ----------------------------
                                           FAHIM SAHRAIE
                                           President/Director




                                        By: /s/ HASHEM SAHRAIE
                                           ---------------------------
                                           HASHEM SAHRAIE
                                           Secretary/Director