US Patent No. 8,052,983 B2; Galderma Laboratories, Inc., Fort Worth, TX, has patented a method of treating acne that comprises administering systemically a tetracycline compound in an amount that is effective to treat acne but has substantially no antibiotic activity, without administering a bisphosphonate compound. The tetracycline compound is a non-antibiotic tetracycline compound, or a pharmaceutically acceptable salt of a non-antibiotic tetracycline compound.