To determine the antimicrobial and anti-inflammatory efficacy of Opuntia ficus-indica for chronic otitis, we evaluated the effects of topical applications of the methanol extracts with 20 cases of dogs which had chronic malignant otitis by pathogens with antibiotic resistance. The dogs had revealed recurrent symptoms of malignant otitis and were not treated by conventional therapeutic agents. However, in this study, the clinical cure rates of Opuntia ficus-indica was 75% and the average alleviation period was $1.21{pm}0.42$ week, and the mean recovery period was $1.06{pm}1.06$ week after the initiation of treatment. As the results of this study, topical Opuntia ficus-indica extracts was found to be highly effective for the treatment of chronic malignant otitis with clinical cure rates of 75% within 1.06 weeks of therapy. Further evaluation of Opuntia ficus-indica extracts will allow us to establish and to optimize the therapeutic strategy for the malignant otitis in veterinary practice, and the potential usefulness of this complementary treatment on recurrent infectious pathology.