A combination therapy for treating a bacterial biofilm comprises a therapeutically effective amount of an antibiotic comprising an aminoglycoside or tetracycline, or a combination of two or more thereof, and a cationic porphyrin in an amount effective for enhancing the effectiveness of the antibiotic in treating the bacterial biofilm. A method of treating a bacterial biofilm comprising Pseudomonas aeruginosa comprises contacting the bacterial biofilm with a combination therapy comprising a therapeutically effective amount of an antibiotic, and a cationic porphyrin in an amount effective for enhancing the effectiveness of the antibiotic in treating the bacterial biofilm. A method of treating a bacterial biofilm comprising Pseudomonas aeruginosa in a patient comprises administering to the patient a combination therapy comprising a therapeutically effective amount of an antibiotic, and a cationic porphyrin in an amount effective for enhancing the effectiveness of the antibiotic in treating the bacterial biofilm.
