Exhibit 31.1

# CERTIFICATION

I, Bruce A. Peacock, certify that:

|1. |  | I have reviewed this quarterly report on Form 10-Q of Adolor Corporation;
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|2. |  | Based on my knowledge, this quarterly report does not contain any untrue
               statement of a material fact or omit to state a material fact necessary to make
               the statements made, in light of the circumstances under which such statements
               were made, not misleading with respect to the period covered by this quarterly
               report;
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|3. |  | Based on my knowledge, the financial statements, and other financial information
               included in this quarterly report, fairly present in all material respects the
               financial condition, results of operations and cash flows of the registrant as
               of, and for, the periods presented in this quarterly report;
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|4. |  | The registrants other certifying officer and I are responsible for
               establishing and maintaining disclosure controls and procedures as defined in
               Exchange Act Rules 13a-15(e) and 15d-15(e), for the registrant and we have:
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|a) |  | designed
such disclosure controls and procedures, or caused such disclosure
               controls and procedures to be designed under our supervision to ensure
that                material information relating to the registrant, including its
consolidated                subsidiaries, is made known to us by others within those
entities, particularly                during the period in which this quarterly report is
being prepared;
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|b) |  | evaluated
the effectiveness of the registrants disclosure controls and
               procedures and presented in this report our conclusions about the
effectiveness                of the disclosure controls and procedures, as of the end of
the period covered                by this report based on such evaluation; and
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|c) |  | disclosed
in this report any change in the registrants internal control                over
financial reporting that occurred during the registrants most recent
               fiscal quarter that has materially affected, or is reasonably likely to
               materially affect, the registrants internal control over financial
               reporting; and
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|5. |  | The registrants other certifying officer and I have disclosed, based on
               our most recent evaluation of internal control over financial reporting, to the
               registrants auditors and the audit committee of registrants board of
               directors:
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|a) |  | all
significant deficiencies and material weaknesses in the design or operation
               of internal controls over financial reporting which are reasonably likely
to                adversely affect the registrants ability to record, process,
summarize and                report financial information; and
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|b) |  | any
fraud, whether or not material, that involves management or other employees
               who have a significant role in the registrants internal controls
over                financial reporting.
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Date: August 7, 2003

/s/Bruce A. Peacock

Bruce A. Peacock President, Chief
Executive Officer and Director