EXHIBIT 10(a)

SIXTH AMENDMENT TO EMPLOYMENT AGREEMENT

THIS SIXTH AMENDMENT to the Employment Agreement by and between SCHERING-PLOUGH
CORPORATION, a New Jersey corporation (the "Company"), and RICHARD J. KOGAN (the
"Employee"), dated as of September 26, 1989, as amended as of June 28, 1994, and
as further amended as of March 1, 1995, and as further amended as of October 24,
1995, and as further amended as of February 25, 1998, and as further amended as
of November 1, 1998 (as so amended, the "Employment Agreement") is made and
entered into as of this 15th day of May, 2002.

WHEREAS, the Company and the Employee wish to amend the Employment Agreement as
set forth below;

NOW, THEREFORE, in consideration of the mutual promises, covenants and
agreements set forth below, it is hereby agreed as follows:

1. Section 3 of the Employment Agreement is hereby amended by adding a new
subsection at the end thereof, reading in its entirety as follows:

(m) Interaction of Basic SERP and SRP. For the avoidance of doubt, the SRP
provided hereunder shall not be treated as "Other Retirement Income" for
purposes of the Basic SERP, notwithstanding any provision of the Basic SERP.

2. Section 4(e) of the Employment Agreement is hereby amended to read in its
entirety as follows:

Date of Termination

. "Date of Termination" means the date on which the Employee's employment
terminates, which shall be as follows: (i) if the Employee's employment is
terminated by the Company for Cause, or by the Employee during the Window Period
or for Good Reason, the Date of Termination shall be the date of receipt of the
Notice of Termination or any later date specified therein, as the case may be;
(ii) if the Employee's employment is terminated by the Company other than for
Cause or Disability, the Date of Termination shall be the date on which the
Company notifies the Employee of such termination or any later date specified in
such notice, as the case may be; and (iii) if the Employee's employment is
terminated by reason of death or Disability, the Date of Termination shall be
the date of death of the Employee or the Disability Effective Date, as the case
may be; provided, that notwithstanding the foregoing, if the Employee's
employment is deemed to have been terminated by the Company without Cause, or to
have been terminated by the Employee without Good Reason, in each case pursuant
to Section 5(g) below, the "Date of Termination" shall be the last day of the
Employment Period.

3. Section 5(a) of the Employment Agreement is hereby amended by revising
subparagraph (iv) to end after the first occurrence of the phrase "Date of
Termination" (and the references in subparagraph (j)(i)(IV)(AAAA) of Section 3
above to "final average earnings" and "deemed compensation" shall be
disregarded), and adding a new subparagraph (v) at the end thereof, reading in
its entirety as follows:

(v) all options to acquire stock of the Company and all other awards based upon
stock of the Company that the Employee has been granted by the Company within 12
months prior to the Date of Termination that remain outstanding but unvested
immediately before the Date of Termination in accordance with their terms shall
be fully vested and (if applicable) exercisable as of the Date of Termination,
notwithstanding any provision to the contrary in the plan under which they were
granted or in any applicable award agreement; provided that vesting of any of
the Employee's awards based upon the stock of the Company that is contingent on
the achievement of performance criteria shall occur only if and to the extent of
the actual achievement of such performance criteria.

4. A new Section 13 is added to the Employment Agreement, reading in its
entirety as follows:

Special Liability Protections

. It is anticipated that the Employee will become a signatory to a consent
decree arising in connection with the Company's pending proceedings with the
Food and Drug Administration (the "Injunction Order"). In consideration for the
Employee's signing the Injunction Order, the Company:

(a) shall take all reasonable steps to help assure that if the Injunction Order
remains in effect at the time of the termination of the Employee's employment
for any reason, the Employee shall cease to be bound by the Injunction Order as
of the Date of Termination (including by paying or reimbursing the Employee for
all reasonable attorneys' fees and expenses that he reasonably incurs to ensure
that such cessation occurs);

(b) shall, except to the extent that it is prohibited from doing so by
applicable law, indemnify the Employee against any settlement amounts, damages,
fines, or penalties that the Employee may incur as a result of any claim
alleging any violation of the Injunction Order, and costs and expenses
(including reasonable attorneys' fees and expenses) that the Employee reasonably
incurs in defending himself in any such claim; and

(c) hereby confirms to the Employee that (1) the indemnification provisions
contained in the Company's Certificate of Incorporation apply to the proceedings
leading to the Injunction Order and any claims relating to or arising out of the
facts underlying the Injunction Order, including without limitation any
shareholder derivative suits, and (2) the Employee's signing the Injunction
Order will not be taken into account in determining whether he has met the
applicable standards to be entitled to indemnification under such provisions.

5. The Employment Agreement is amended, in each relevant Section thereof, so
that any and all references to the Company's termination of the Employee's
employment "other than for Cause" or "without Cause," and the Employee's
termination of employment for "Good Reason" (or similar phrasing relating to
either of such circumstances) shall be replaced with a deemed reference under
such circumstances to the Employee's "retirement at the request of the Company"
(it being agreed and understood that the intent of this provision is not to
change any benefits payable to the Employee under the Employment Agreement, but
to more precisely characterize the actions of the Company in the event of the
cessation of the Employee's employment under such circumstances given the
Employee's age and service with the Company as of the date of this Sixth
Amendment).

6. Notwithstanding the foregoing, this Sixth Amendment shall have no force or
effect unless and until the Employee in fact becomes a signatory to the
Injunction Order.

7. Except as provided above, the Employment Agreement shall continue in effect
without alteration as in effect on the date hereof. The Employment Agreement, as
previously amended and as amended by this Sixth Amendment, constitutes the
entire agreement of the parties and supersedes all prior agreements and
understandings with respect to the subject matter hereof and thereof.

IN WITNESS WHEREOF, the Employee and, pursuant to due authorization from its
Board of Directors, the Company have caused this Agreement to be executed as of
the day and year first above written.

/s/Richard J. Kogan

SCHERING-PLOUGH CORPORATION

/s/Jack L. Wyszomierski
Executive Vice President and
Chief Financial Officer