1. A composition comprising rifaximin in the form of particles, wherein substantially all the particles have a particle size of less than or equal to 2 mkm.2. A composition according to claim 1, wherein substantially all the particles have a particle size of less than or equal to 1 mkm.3. A composition according to claim 1 or 2, further comprising at least one surface stabilizer, at least one thickening agent and / or at least one polymer, wherein substantially all the particles have a particle size of less than or equal to 2 mkm.4 . A composition according to claim 3, wherein the, substantially all the particles have a particle size of less than or equal to 1 mkm.5. A composition according to claim 3, wherein the surface stabilizer is a surfactant veschestvo.6. A composition according to claim 5, wherein the surfactant is an amphoteric, nonionic, cationic or anionic surfactant veschestvo.7. A composition according to claim 5, wherein the surfactant is a polysorbate sodium dodecyl sulphate (sodium lauryl sulphate) laurildimetilaminoksid sodium docusate cetyltrimethylammonium bromide (CTAB) polyethoxylated alcohol polyoxyethylene octoxynol N, N-dimethyldodecylamine-N-oxide hexadecyltrimethylammonium bromide, polyoxyl 10 lauryl ether, polyoxyethylene esters, bile acid salt, such as sodium deoxycholate or sodium cholate polyoxyl castor oil nonylphenol ethoxylate cyclodextrin lecithin metilbenzetoniya chloride carboxylate sulfonate petroleum sulfonate alkylbenzenesulfonates naphthalene sulfonate, and olefin sulfonated surfactant alkyl sulfate sulfated natural oil or fat1. Композиция, содержащая рифаксимин в форме частиц, в которой, по существу, все частицы имеют размер частиц, меньший или равный 2 мкм.2. Композиция по п.1, в которой, по существу, все частицы имеют размер частиц, меньший или равный 1 мкм.3. Композиция по п.1 или 2, дополнительно содержащая по меньшей мере один стабилизатор поверхности, по меньшей мере один загуститель и/или по меньшей мере один полимер,
