EXHIBIT 24-A

**POWER OF ATTORNEY**

     Each person whose signature appears below hereby authorizes and appoints  Douglas D. Burkett, Ph. D. and Lawrence J. Batina, and each of them severally, as his attorneys-in-fact, with full power of substitution and resubstitution, to sign and file on his  behalf individually and in each such capacity stated below,  Zila, Inc.’s Annual Report on Form 10-K for the year ending July 31, 2003, and any amendments thereto, to be filed with the Securities and Exchange Commission, The NASDAQ Stock Market, and otherwise, as fully as such person could do in person, hereby verifying and confirming all that said attorneys-in-fact, or their or his substitutes or substitute, may lawfully do or cause to be done by virtue hereof.

| **Signatures**                                    |   | **Title**                                                          |   | **Date**          |
|---------------------------------------------------|--------|--------------------------------------------------------------------|--------|-------------------|
|                                                   |   |                                                                    |   |                   |
|                                              |   |                                                               |   |              |
|                                              |   | President and Chief   Executive Officer and a Director             |   | September 4, 2003 |
|                                                   |   |                                                               |   |
| **Douglas D.   Burkett**,**Ph. D.**               |   |                                                               |   |              |
| **Principal Executive Officer**                   |   |                                                               |   |              |
|                                              |   |                                                               |   |              |
| /s/LAWRENCE J. BATINA                             |   | Vice President, Chief Financial   Officer, Treasurer and Secretary |   | September 4, 2003 |
|                                                   |   |                                                               |   |
| **Lawrence   J. Batina**                          |   |                                                               |   |              |
| **Principal****Financial and Accounting Officer** |   |                                                               |   |              |
|                                              |   |                                                               |   | September 4, 2003 |
| **Directors**                                     |   |                                                               |   |              |
|                                              |   |                                                               |   |              |
|                                              |   |                                                               |   | September 4, 2003 |
|                                                   |   |                                                               |   |              |
| **Morris C.   Aaron**                             |   |                                                               |   |              |
|                                              |   |                                                               |   | September 4, 2003 |
|                                              |   |                                                               |   |              |
|                                                   |   |                                                               |   |              |
| **Christopher   D. Johnson**                      |   |                                                               |   |              |
|                                              |   |                                                               |   |              |
|                                              |   |                                                               |   | September 4, 2003 |
|                                                   |   |                                                               |   |              |
| **Michael S.   Lesser**                           |   |                                                               |   |              |
|                                              |   |                                                               |   |              |
|                                              |   |                                                               |   | September 4, 2003 |
|                                                   |   |                                                               |   |              |
| **John   Edward Porter**                          |   |                                                               |   |              |
|                                              |   |                                                               |   |              |
|                                              |   |                                                               |   | September 4, 2003 |
|                                                   |   |                                                               |   |              |
| **S. Timothy   Rose, D.D.S.**                     |   |                                                               |   |              |
|                                              |   |                                                               |   |              |
|                                              |   |                                                               |   | September 4, 2003 |
|                                                   |   |                                                               |   |              |
| **Kevin J.   Tourek**                             |   |                                                               |   |              |