A topical therapeutic hydrophobic breakable composition comprises a carrier, which includes: (a) about 60% to about 99% by weight of at least one hydrophobic oil； (b) at least one viscosity-modifying agent selected from the group consisting of a fatty alcohol, a fatty acid and a wax； and (c) a tetracycline antibiotic. The viscosity of the composition is at least about 30% higher than the viscosity of the carrier without the tetracycline antibiotic； and is higher than the viscosity of the hydrophobic oil and the tetracycline antibiotic without the viscosity modifying agents. The tetracycline is chemically stable in the composition for at least six months； wherein more than about 90% of the tetracycline has not broken down. When packaged in an aerosol container, the composition affords upon release from the container a breakable foam of at least good quality that breaks easily upon application of shear force.
