EXHIBIT 5






August 10, 2004


Schering-Plough Corporation
2000 Galloping Hill Road
Kenilworth, New Jersey 07033

Dear Sirs:

Reference  is made to our opinion  dated March 2, 2004,  and included as Exhibit
5.2 to the  Registration  Statement  on Form  S-3  (File  No.  333-113222)  (the
"Registration   Statement")   filed  on  March  2,  2004,   by   Schering-Plough
Corporation,  a New Jersey corporation (the "Company"),  with the Securities and
Exchange  Commission  (the  "Commission")  under the  Securities Act of 1933, as
amended (the "Securities  Act"). We are rendering this  supplemental  opinion in
connection  with a prospectus  supplement  to the  Registration  Statement  (the
"Prospectus  Supplement")  filed by the Company with the Commission on August 5,
2004,  pursuant  to Rule  424(b)(5)  promulgated  under  the  Securities  Act in
connection with the offering by the Company of 28,750,000  shares (the "Shares")
of the Company's 6.00% Mandatory  Convertible  Preferred  Stock, par value $1.00
per share,  pursuant to an underwriting  agreement,  dated as of August 4, 2004,
between  the  Company  and  the  several  underwriters  specified  therein  (the
"Underwriting Agreement").

In  this   connection,   we  have  examined  and  relied   without   independent
investigation  as to matters of fact upon such  statements and  certificates  of
public  officials,  such statements and certificates of officers of the Company,
the  Registration  Statement,   the  Prospectus  Supplement,   the  Underwriting
Agreement, the certificate of incorporation and bylaws of the Company as amended
and now in effect, including,  without limitation,  the certificate of amendment
to the Company's  certificate of incorporation filed on August 5, 2004, with the
State of New Jersey (the  "Certificate of Amendment"),  proceedings of the board
of  directors  of the  Company,  such  other  corporate  records,  certificates,
documents  and  instruments  and  such  questions  of law as we have  considered
necessary or  appropriate  for the purposes of this opinion.  In rendering  this
opinion we have  assumed the  genuineness  of all  signatures  on all  documents
examined by us, the due  authority of the parties  signing such  documents,  the
authenticity of all documents submitted to us as originals and the conformity to
the originals of all documents submitted to us as copies.




Schering-Plough Corporation
Page 2




Based on the foregoing,  and subject to the  limitations set forth below, we are
of the opinion that:

1.        The Shares,  when issued by the Company and  delivered  by the Company
          against  payment   therefor  in  accordance  with  the  terms  of  the
          Underwriting  Agreement,  will  be  validly  issued,  fully  paid  and
          nonassessable.

2.        The shares of the Company's  common stock,  par value $0.50 per share,
          issuable upon conversion of the Shares, when issued in accordance with
          terms of the Certificate of Amendment,  will be validly issued,  fully
          paid and nonassessable.

This opinion is limited to the provisions of the New Jersey Business Corporation
Act.

We  hereby  consent  to  the  filing  of  this  opinion  as an  exhibit  to  the
Registration  Statement  and to the  references  to this firm under the  heading
"Legal Matters" in the prospectus  included in the  Registration  Statement.  In
giving  such  consent,  we do not thereby  admit that we are in the  category of
persons whose consent is required under Section 7 of the Act.

Very truly yours,

/s/ LOWENSTEIN SANDLER PC

LOWENSTEIN SANDLER PC