A tetracycline salt comprising a tetracycline and an organic acid wherein the organic acid is oxalic acid or maleic acid is provided. The tetracycline is preferably doxycycline, minocycline, sancycline, lymecycline, tetracycline or demeclocycline, and preferred salts include oxycycline maleate, minocycline oxalate, tetracycline oxalate, demeclocycline maleate, demeclocycline oxalate, sancycline maleate, lymecycline maleate, or lymecycline oxalate. A pharmaceutical formulation comprising a tetracycline salt according to the invention is also provided, as is a medical device having coated thereon a salt or pharmaceutical formulation according to the invention. A salt of the invention, or a formulation of the invention are also provided for use as medicaments, particularly for use in the treatment or prevention of an inflammation and/or an infection. There is also provided a method of preparing a tetracycline salt, which method comprises reacting a tetracycline base with an excess of an organic acid in a solvent.