An antimicrobial detergent composition comprises (a) an organic surfactant; (b) a water-soluble cationic polymer selected from the group consisting of polyethyleneimines and alkoxylated polyethylenimines having molecular weight greater than 100; and (c) a particulate heavy metal salt of 2-pyridinethiol-1-oxide. For (a), anionic organic surfactants, e.g. alkyl glyceryl ether sulphonates, N-acyl sarcosinates, alkyl ether ethylene oxide sulphates, soaps and lower alkanolamine salts of fatty acids; polar nonionic surfactants, e.g. amine and phosphine oxides; and amphoteric surfactants, e.g. alkyl beta-iminodipropionates, alkyl beta-aminopropionates and certain long chain imidazole derivatives, are preferably used, excellent results being obtained with a mixture of from 4 to 20% by weight of the total composition of (i) a non-soap organic anionic surfactant; and (ii) a polar nonionic, zwitterionic or amophoteric surfactant. Nonionic surfactants, e.g. "Pluronics" (Registered Trade Mark), polyethylene oxide condensates of alkyl phenols, condensates of ethylene oxide with the product resulting from the reaction of propylene oxide and ethylene diamine or with aliphatic alcohols; and cationic surfactants, e.g. distearyl dimethyl ammonium chloride, stearyl dimethyl benzyl ammonium chloride, coconut alkyl dimethyl benzyl ammonium chloride, dicoconut alkyl dimethyl ammonium chloride, cetyl pyridinium chloride and cetyl trimethyl ammonium bromide, may also be used for (a).  The polymers (b) preferably have a molecular weight within the range from 3000 to 100,000 and are preferably employed at a concentration within the range from 0.25 to 2.00% by weight of the total composition.  The preferred salts for (c) are zinc, cadmium, tin and zirconium 2-pyridinethiol-1-oxides and are preferably used in the range from 0.5 to 2.0% by weight of the total composition.  Additional additives include organic solvents, such as ethanol; thickeners, e.g. carboxymethyl cellulose, magnesium aluminium silicate, hydroxyethyl- or methyl-celluslose; perfumes; sequestering agents such as tetra-sodium ethylenediamine tetraacetate; opacifiers such as zinc or magnesium stearate; suds boosters such as coconut acyl mono- or diethanolamides; and salts such as sodium chloride or sulphate.ALSO:Antimicrobial detergent compositions particularly useful in the treatment of dandruff comprise (a) an organic surfactant, (b) a water-soluble cationic polymer selected from the group consisting of polyethylenimines and alkoxylated polyethylenimines having molecular weight greater than 100, and (c) a particulate heavy metal salt of 2-pyridinethiol-1-oxide.  For (a), anionic organic surfactants, e.g. alkyl glyceryl ether sulphonates, N-acyl sarcosinates, alkyl ether ethylene oxide sulphates, soaps and lower alkanolamine salts of fatty acids; polar nonionic surfactants, e.g. amine and phosphine oxides; and amphoteric surfactants, e.g. alkyl beta-iminodipropionates, alkyl beta-aminopropionates and certain long chain imidazole derivatives, are preferably used, excellent results being obtained with a mixture of from 4 to 20% by weight of the total composition of (i) a non-soap organic anionic surfactant and (ii) a polar nonionic, zuritherionic or amphoteric surfactant.  Nonionic surfactants, e.g. "Pluronics" (trade mark), polyethylene oxide condensates of alkyl phenols, condensates of ethylene oxide with the product resulting from the reaction of propylene oxide and ethylene diamine or with aliphatic alcohols; and cationic surfactants, e.g. distearyl dimethyl ammonium chloride, stearyl dimethyl benzyl ammonium chloride, coconut alkyl dimethyl benzyl ammonium chloride, dicoconut alkyl dimethyl ammonium chloride, cetyl pyridinium chloride and cetyl trimethyl ammonium chloride, may also be used for (a) the polymers (b) preferably have a molecular weight within the range from 3,000 to 100,000 and are preferably employed at a concentration within the range from 0.25 to 2.00% by weight of the total composition.  The preferred salts for (c) are zinc, cadmium, tin and zirconium 2-pyridinethiol-1-oxides and are preferably used in the range from 0.5 to 2.0% by weight of the total composition.  Additional additives include organic solvents, such as ethanol; thickeners, e.g. carboxymethyl cellulose, magnesium aluminium silicate, hydroxyethyl-or methyl-cellulose; perfumes; sequestering agents such as tetra-sodium ethylenediamine tetraacetate, opacifiers such as zinc or magnesium stearate; suds boosters such as coconut acyl mono- or diethanolamides; and salts such as sodium chloride or sulphate.