EXHIBIT 31.1

CERTIFICATIONS

     I, Douglas D. Burkett, certify that: 

     1. I have reviewed this annual report on Form 10-K of Zila, Inc.

     2. Based on my knowledge, this 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 report;

     3. Based on my knowledge, the financial statements, and other financial information included in this 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 report;

     4. The registrant’s other certifying officer(s) 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 have:

|   | 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 report is being prepared;                              |
|--------|--------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
|   |   |                                                                                                                                                                                                                                                                                                                                                                                                                  |
|   | 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                                                                                                                      |
|   |   |                                                                                                                                                                                                                                                                                                                                                                                                                  |
|   | 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 (the registrant’s   fourth fiscal quarter in the case of an annual report) that has materially   affected, or is reasonably likely to materially affect, the registrant’s   internal control over financial reporting; and |

     5. The registrant’s other certifying officer(s) 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 (or persons performing the equivalent functions):

|   | a)     | All significant deficiencies   and material weaknesses in the design or operation of internal control over   financial reporting which are reasonably likely to adversely affect the   registrant’s ability to record, process, summarize and report financial   information; and |
|--------|--------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
|   |   |                                                                                                                                                                                                                                                                                   |
|   | 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.                                                                                                   |

Date: October 27, 2003

| /s/   DOUGLAS D. BURKETT Ph. D. |
|---------------------------------|
|                                 |
| **Douglas D. Burkett Ph. D.**   |
| **Chief Executive Officer**     |