The problem of formulating a dentifrice which is compatible with a bis-biguanide anti-bacterial agent, for instance chlorhexidine or alexidine, is solved by using a nonionic thickening agent; a nonionic surfactant; and an abrasive which is either a sparingly soluble salt, for instance calcium carbonate, (used in combination with an agent to suppress anion formation), or an essentially insoluble compound, for instance, a silica of low anion content, or a mixture thereof. Preferably, the composition has a flavour which is mainly aniseed, balanced by mints. Preferably during the preparation of a silica containing dentifrice, chlorhexidine and saccharin are added together at an early stage, prior to the addition of silica, to avoid the formation of lumps. Such dentifrices are useful in the prophylaxis and/or treatment of periodontal disease and caries.