Context • Vulvovaginal candidiasis is the most common infection of the vulvovagina, which manifests with itching, a burning sensation, and leucorrhea. Some infections have been reported to be tolerant to conventional treatments, especially in immunosuppressed patients. New studies have suggested that ozone, which is the allotropic form of oxygen, may have antifungal effects. Objective • The study intended to compare the effects of ozononated olive oil and clotrimazole in the treatment of vulvovaginal candidiasis. Design • Patients were randomly assigned either to an ozone group or to a clotrimazole group in a randomized, controlled trial. Setting • The study took place in the Department of Gynecology of the School of Medicine at Mashhad University of Medical Sciences in Mashhad, Iran. Participants • Participants were 100 female patients who had been referred to the women's gynecology clinic at the Omolbanin and Ghaem Hospitals and who had confirmed vulvovaginal candidiasis. Intervention • Patients in the ozone group were treated with ozonated olive oil or those in the clotrimazole group were treated with clotrimazole for 7 d. Outcome Measures • Patients were evaluated through an interview and a paraclinical examination at baseline and postintervention. The study measured changes in itching, burning, and leucorrhea using a questionnaire that patients completed at the end of the study and determined the presence of an infection with vaginal candidiasis through a culture both before acceptance into the study and after the treatments, if accepted. Results • Ozone and clotrimazole both reduced symptoms significantly and led to a negative culture for vaginal candidiasis (P < .05). No significant differences existed between the 2 groups in their effects on the symptom of itching and leucorrhea and on the results of the culture (P > .05). However, clotrimazole decreased the burning sensation significantly more than did ozone (P < .05). Conclusions • Considering the potential efficacy of ozonated olive oil in the improvement of the clinical and paraclinical aspects of treatment of patients with vulvovaginal candidiasis, the research team suggests that the treatment can be an effective topical treatment for those patients.