Exhibit 99.11
CONSENT OF PERSON ABOUT TO BECOME A DIRECTOR
Pursuant to Rule 438 promulgated under the Securities Act of 1933, as amended, the undersigned
hereby consents to be named as a person about to become a director of Schering-Plough Corporation
(to be renamed Merck & Co., Inc.) in the Registration Statement on Form S-4 filed by
Schering-Plough Corporation with the Securities and Exchange Commission (File No. 333-159371) under
the Securities Act of 1933, as amended.
| /s/ Richard T. Clark | ||||
| Name: | Richard T. Clark | |||
June 12, 2009