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                                                                    EXHIBIT 4.3

                            FIRST HEALTH GROUP CORP.

                             STOCK OPTION AGREEMENT


         THIS AGREEMENT is made and entered into as of the 20th day of March,
2001, by and between FIRST HEALTH GROUP CORP., a Delaware corporation (the
"Company"), and EDWARD L. WRISTEN (the "Employee").

         WHEREAS, the Employee is a valued employee of the Company and the
Company wishes to induce him to enter into an employment agreement dated as of
March 20, 2001 (the "Employment Agreement") and to provide financial incentives
to further encourage him in the performance of his duties thereunder by granting
him an option to purchase shares of common stock, $.01 par value, of the Company
(the "Common Stock");

         WHEREAS, the Employee wishes to acquire the right to purchase shares of
Common Stock.

         NOW, THEREFORE, for good and valuable consideration, the parties
hereto, intending to be legally bound, hereby agrees as follows:

         1. Grant of Option. Subject to the provisions of Section 2 hereof and
subject to stockholder approval, the Company hereby grants to the Employee
effective as of the date hereof the right, privilege and option to purchase on
the terms and conditions hereinafter set forth up to 100,000 shares of Common
Stock at a purchase price of $45.0313 per share (the "Option"). The Option is
intended to be an "Incentive Stock Option" as defined in Section 422 of the
Internal Revenue Code of 1986, as amended (the "Code"), subject to Section 422
of the Code, to the extent permitted by the Code, and a nonstatutory option with
respect to the balance.

         2. Time for Exercise of Option. Subject to the provisions of paragraph
3 and 7 hereof, the Option may be exercised by the Employee from time to time,
in whole or in part, beginning on March 20, 2004 and ending on March 20, 2008,
or within such shorter period as is provided in paragraph 3 hereof.

         3. Termination of Employment.

         (a) If the Employee's employment by the Company is terminated by the
Company without cause, then, notwithstanding the provisions of paragraph 2 of
this Agreement, upon such termination of employment, the Option shall become
exercisable in full and the Employee may, for a period of 90 days following such
termination (but before expiration of the original exercise period), exercise
the Option in whole or in part.

         (b) If the Employee's employment by the Company is terminated due to
death or incapacity (as this term is defined in Employee's Employment Agreement)
or by voluntary, not for cause reasons as allowed under the Employment Agreement
then, notwithstanding Section 2 of this Agreement, the Option shall be entirely
vested and exercisable in full and Employee or his legal representative may, for
a period of two years following such termination (but before expiration of the
original exercise period), exercise the Option in whole or in part.

         (c) If (i) the Employee's employment by the Company is terminated
voluntarily by the Employee and (ii) pursuant to paragraph 2 hereof the Option
has theretofore vested, the Employee may, for a period of 30 days after the date
of the termination (but before expiration of the original exercise period),
exercise the Option, in whole or in part.

         (d) If the Employee's employment by the Company is terminated by the
Company for cause (as such term is defined in the Employment Agreement), the
Option shall terminate on the date on which the Employee's employment is
terminated, and the Employee shall have no further rights hereunder.

         (e) The Employee acknowledges and understands that certain exercises of
the Option pursuant to this paragraph 3 may cause disqualification of the Option
as an Incentive Stock Option.

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         4. Method of Exercise. The Option may be exercised by written notice
(the "Notice"), addressed and delivered to the Company (Attention: Chief
Financial Officer), specifying the number of shares of Common Stock to be
purchased and accompanied by (i) a check, or (ii) that number of shares of
Common Stock which have an aggregate fair market value as of the date of
exercise equal to the exercise price, or (iii) any combination thereof. For
purposes of this Agreement, "fair market value" of a share of Common Stock shall
mean: (i) if the Common Stock is traded on a national stock exchange on the date
of exercise of the Option, fair market value shall be the closing price reported
by the applicable composite transactions report on such day, or if the Common
Stock is not traded on such date, the mean between the closing bid-and-asked
prices thereof on that date on such exchange; (ii) if the Common Stock is traded
over-the-counter and is classified as a national market issue on the date of
exercise of the Option, fair market value shall be the last reported transaction
price quoted by the NASDAQ on that day; (iii) if the Common Stock is traded
over-the-counter and is not classified as a national market issue on the date of
exercise of the Option, fair market value shall be the mean between the last
representative bid-and-asked prices quoted by the NASDAQ on that day; or (iv) if
none of the foregoing provisions is applicable, fair market value as of the date
of exercise of the Option shall be determined by the Board of Directors in good
faith on such basis as it deems appropriate. In all cases, the determination of
fair market value shall be binding and conclusive on all persons.

         5. Delivery of Stock Certificates. The Option shall be deemed to have
been exercised upon receipt by the Company of the Notice accompanied by the
exercise price (the "Exercise Date"). The certificate representing the shares of
Common Stock purchased upon exercise of the Option shall be issued as of the
Exercise Date and delivered by the Company to the Employee free and clear of all
claims, liens and encumbrances, within five days following the Exercise Date or
as soon thereafter as practicable. As a condition to the exercise of the Option,
the Company may require the Employee to represent and warrant at the time of any
such exercise that the shares of Common Stock are being purchased for investment
purposes only, for the account of the Employee and without any intention to
distribute such shares. If the shares of Common Stock issuable upon exercise of
the Option have not previously been registered under the Securities Act of 1933,
as amended (the "Securities Act") as contemplated by this Agreement, each
certificate evidencing shares of Common Stock acquired upon exercise of the
Option shall contain on its face, or on the reverse side thereof, the following
legend:

         "These shares have not been registered under the Securities Act of 1933
         or under any applicable state law. They may not be offered for sale,
         sold, transferred, or pledged without (1) registration under the
         Securities Act of 1933 and any applicable state law, or (2) an opinion
         (satisfactory to the corporation) that registration is not required."

         6. Adjustment Provisions. If, during the term of this Agreement, there
shall be any stock dividend, stock rights distribution, stock split,
recapitalization, merger, consolidation, sale of assets, reorganization or other
similar change or transaction of or by the Company, an appropriate adjustment
shall be made to the number and kind of shares remaining to be acquired upon
exercise of the Option and to the exercise price of the Option so that the value
to be received by the Employee upon exercise of the Option shall, in the
aggregate, be the same as if none of the foregoing transactions had occurred.

         7. Merger, Consolidation or Sale of Assets. In the event the Company
enters into an agreement providing for (i) the sale of all or substantially all
of the assets of the Company or (ii) a merger, consolidation or reorganization
which would result in the stockholders of the Company immediately prior to such
transaction owning less than 50% of the surviving corporation, the Option shall
become exercisable in full without regard to any vesting limitations, and the
Employee shall be entitled, commencing at least ten days prior to the effective
date of such transaction, to exercise the Option in whole or in part, to the
extent not previously exercised.

         8. Withholding Obligations. In the event that the Company is required
to satisfy withholding obligations under the Code as a result of the exercise of
the Option, the Employee may request that, in lieu of withholding amounts from
the Employee's paycheck or requiring that the Employee write a check to the
Company in the amount of the withholding obligation, the Company withhold that
number of shares of Common Stock which have a fair market value (determined in
accordance with the provisions of the Plan) on the Exercise Date equal to the
amount required to be withheld.
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         9. Non-Transferability. The Option is not transferable or assignable by
the Employee other than by will or by the laws of descent and distribution and
are exercisable during the lifetime of the Employee only by the Employee.

         10. Compliance with Law. By accepting the Option, the Employee agrees
for himself and his legal representative that the Company shall not be required
to deliver any shares of Common Stock upon the exercise of the Option until such
shares have been qualified for delivery under applicable securities laws and
regulations as determined by the Company or its legal counsel.

         11. Rights as a Stockholder; Not an Employment Agreement. The Employee
shall have no rights as a stockholder of the Company with respect to shares of
Common Stock subject to the Option until the Option has been exercised and
payment made as herein provided and certificates representing the shares as to
which the Option has been exercised have been delivered to the Employee. Nothing
contained in this Agreement shall be construed to be a contract of employment
between the Company and the Employee.

         12. Construction.

         (a) Successors. This Agreement and all the terms and provisions hereof
shall be binding upon and shall inure to the benefit of the parties hereto and
their respective legal representatives, heirs and successors, except as
expressly herein otherwise provided.

         (b) Entire Agreement; Modification. This Agreement contains the entire
understanding between the parties with respect to the matters referred to herein
and such agreement shall not be modified, except by written instrument signed by
the parties hereto.

         (c) Headings; Pronouns; Governing Law. The descriptive headings of the
respective sections and subsections of this Agreement are inserted for
convenience of reference only and shall not be deemed to modify or construe the
provisions which follow them. Any use of any masculine pronoun shall include the
feminine and vice-versa and any use of a singular, the plural and vice-versa, as
the context and facts may require. The construction and interpretation of this
Agreement shall be governed in all respects by the laws of the State of
Delaware.

         (d) Notices. All communications between the parties shall be in writing
and shall be deemed to have been duly given as of the date and time of hand
delivery or three days after mailing via certified or registered mail, return
receipt requested, proper postage prepaid following or such other addresses of
which the parties shall from time to time notify another:

         If to the Company:                Chief Financial Officer
                                           First Health Group Corp.
                                           3200 Highland Avenue
                                           Downers Grove, Illinois 60515

         If to the Employee:               Edward L. Wristen
                                           First Health Group Corp.
                                           3200 Highland Avenue
                                           Downers Grove, Illinois  60515

         (e) Severability. Whenever possible, each provision of this Agreement
shall be interpreted in such manner as to be effective and valid under
applicable law, but if any provision of this Agreement or the application
thereof to any party or circumstance shall be prohibited by or invalid under
applicable law, such provision shall be ineffective to the minimal extent of
such provision or the remaining provisions of this Agreement or the application
of such provision to other parties or circumstances.


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         IN WITNESS WHEREOF, the parties have executed or caused to be executed
this Agreement as of the date first above written.


                                            FIRST HEALTH GROUP CORP.



                                             By:  /s/  James C. Smith
                                                --------------------------------
                                                  James C. Smith
                                                  Chairman and CEO





                                                  /s/  Edward L. Wristen
                                                --------------------------------
                                                  Edward L. Wristen