The mechanism of oxidative removal of flucloxacillin antibiotic (Flx) by two different oxidants (Ox), potassium bromate (KBrO3) and potassium iodate (KIO3), were studied using a spectrophotometric technique in sulfuric acid medium. The stoichiometry of the oxidation reactions of flucloxacillin by both oxidants was set to be a 2: 3 (Ox: Flx). The oxidation products of flucloxacillin were identified utilizing spot tests and FT-IR spectroscopy. The reactions followed a first order credence in [Flx] and lesser than unit order kinetics regarding to both [Ox] and [H+]. Negligible impacts of both ionic strength and dielectric constant of the reactions medium on the rates of reactions were observed. The dependence of the oxidation rates on mercuric acetate concentration which works as a scavenger for any bromide or iodide ion composed during the reactions was investigated. Credence of reaction rates on temperature was studied, and the activation parameters were assessed and discussed. Tests for free radicals involvement throughout the oxidation reactions were negative. The reactions mechanism was elucidated and the rate law expressions were derived.