EXHIBIT 99.1

CERTIFICATION PURSUANT TO 18 U.S.C. SECTION 1350,

AS ADOPTED PURSUANT TO SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

In connection with the Quarterly Report of IVAX Corporation (the “Company”) on Form 10-Q for the period ending March 31, 2003, (the “Report”), as filed with the Securities and Exchange Commission on the date hereof, I, Phillip Frost, M.D., Chairman and Chief Executive Officer, certify pursuant to 18 U.S.C. §1350, as adopted pursuant to §906 of the Sarbanes-Oxley Act of 2002, that:

1. The Report fully complies with the requirements of section 13(a) or 15(d) of the Securities Exchange Act of 1934, as amended; and

2. The information contained in the Report fairly presents in all material respects, the financial condition and results of operations of the Company.

/s/    PHILLIP FROST, M.D.

Phillip Frost, M.D.

Chairman and Chief Executive Officer

May 14, 2003