A tooth-cleansing agent comprises as tartar-dissolving agent, a water-soluble salt of an amino methylene carboxylic acid which contains at least two methylene carboxylic acid groups, and in which the ratio between the number of the methylene carboxylic acid groups and the basic nitrogen atoms is at least one, in admixture with the usual ingredients of tooth-cleansing agents. Suitable salts are the sodium, potassium, lithium, ammonium, and amine salts, e.g. diethylamine, monoethylamine and hydroxyalkylamine such as the mono-, di-, and particularly the tri-ethanolamine, and diethylaminoethanol salts.  The salts may be those of the reaction products of chloracetic acid with alkylene diamines, e.g. ethylene diamine, or with polyalkylene polyamines, e.g. diethylenetriamine, and of the reaction products of chloracetic acid with condensation products obtained from formaldehyde and alkylene polyamines, e.g. diethylenetriamine, and of the reaction products of dibasic acids, e.g. oxalic acid and malonic acid, with diglycolamic acid.  The water - soluble salts of ethylene diamine tetracetic acid and of diglycolamic acids and triglycolamic acid of the formulae <FORM:0490384/IV/1> and <FORM:0490384/IV/2> may be used.  In the first formula, R stands for hydrogen or an alkyl or aryl group, e.g. the methyl, ethyl, hydroxyethyl or phenyl group.  Tri-sodium and triethanolamine salts of triglycolamic acid are particularly efficacious.  The Specification as open to inspection under Sect. 91 comprises also the following subject-matter: in the first formula above, R may stand for an aralkyl group such as benzyl; water-soluble salts of the reaction products of chloracetic acid with dimethylethylenediamine may be used.  This subject-matter does not appear in the Specification as accepted.ALSO:A tooth-cleansing agent comprises as tartar-dissolving agent, a water-soluble salt of an amino methylene carboxylic acid which contains at least two methylene carboxylic acid groups, and in which the ratio between the number of the methylene carboxylic acid groups and the basic nitrogen atoms is at least one, in admixture with the usual ingredients of tooth-cleansing agents such as filling or mechanical cleansing agents, e.g. bolus alba, kaolin, diatomaceous earth, silica gel, talc or water insoluble artificial resins, capillary active substances, e.g. soap, alcohol sulphonates, condensation products obtained from high molecular carboxylic acids and amino- or hydroxy-carboxylic acids or amino- or hydroxy-sulphonic acids, reaction products of alkylene oxides with higher molecular compounds containing reactive hydrogen atoms, or condensation products of higher molecular fatty acids with polyvalent amines, disinfecting agents, e.g. phenol, higher amines or ammonium compounds, bleaching agents, e.g. hydrogen peroxide, potassium chlorate or potassium permanganate, flavouring substances, e.g. peppermint oil, and glycerine, the ingredients being so selected that they do not react with the specified salt.  There may be present other substances displaying a tartar-dissolving action, preferably water-soluble meta- and pyrophosphates, for example, sodium hexametaphosphate prepared by melting primary phosphates with subsequent rapid cooling.  The secondary and quaternary sodium, potassium, lithium, ammonium and amine salts of pyrophosphoric acid are also specified.  Water-soluble salts of the amino methylene carboxylic acids used are the sodium, potassium, lithium, ammonium, and amine salts, e.g. diethylamine, monoethylamine and hydroxyalkylamine such as the mono-, di- and particularly the triethanolamine, and diethylaminoethanol salts. The salts may be those of the reaction products of chloracetic acid with alkylene diamines, e.g. ethylene diamine, or with polyalkylene polyamines, e.g. diethylene triamine, and of the reaction products of chloracetic acid with condensation products obtained from formaldehyde and alkylene polyamines, e.g. diethylenetriamine, and of the reaction products of dibasic acids, e.g. oxalic acid and malonic acid, with diglycolamic acid. The water soluble salts of ethylene diamine tetracetic acid and of diglycolamic acids and triglycolamic acids of the formulae <FORM:0490384/VI/1> and <FORM:0490384/VI/2> may be used. In the first formula, R stands for hydrogen or an alkyl or aryl group, e.g. the methyl, ethyl, hydroxy-ethyl or phenyl group. Tri-sodium and triethanolamine salts of triglycolamic acid are particularly efficacious.  An example of a dentifrice is given.  The Specification as open to inspection under Sect. 91 comprises also a reference to gargles comprising water-soluble salts of the amino-methylene carboxylic acids, and the following subject-matter. In the first formula above, R may stand for an aralkyl group such as benzyl; water-soluble salts of the reaction products of chloracetic acid with dimethylethylenediamine may be used; cresol, benzyl phenol, and mixtures of higher molecular alkyl-dimethyl benzyl ammonium chlorides may be used as disinfecting agents; and another example of a dentifrice.  This subject-matter does not appear in the Specification as accepted.