Abstract: Novel morpholino compounds having the general formula ##STR1## wherein R.sub.1 is a straight or branched alkyl group containing 8 to 16 carbon atoms at the 2- or 3-position of the morpholino ring, and R.sub.2 is a straight or branched alkyl group containing 2 to 10 carbon atoms, substituted with a hydroxy group except in the alpha-position, the sum of the carbon atoms in the groups R.sub.1 and R.sub.2 being at least 10 and preferably 10 to 20; and pharmaceutically acceptable salts thereof. Compositions for the treatment of the oral cavity and especially the tooth surfaces containing the novel compound or a salt thereof, preferably from 0.1 to 5% by weight thereof. Use of the compounds to inhibit the formation of dental plaque or remove plaque already formed by application of the compound in an aqueous solution or a composition to the surfaces of the oral cavity, especially the surfaces of the teeth. Processes for the preparation of the compounds.