Quaternary ammonium salts containing at least one hydroxyalkyl group are obtained by treating an ammonium or amine salt with an alkylene oxide at a raised pressure, the alkylene oxide being taken in about the minimum amount theoretically necessary for the production of a quaternary salt or in a slight excess over that amount; thus, a salt of a tertiary amine is treated with one mol. of alkylene oxide, or slightly more, per mol. of amine, while a salt of a secondary amine is treated with two mols. of alkylene oxide, or slightly more, per mol. of amine. The reaction may be effected at a temperature up to 100 DEG C. in the presence or absence of water, and the products may be converted into the corresponding quaternary ammonium bases. The products are useful as dyestuff intermediates and for pharmaceutical purposes, and also as assistants in the textile industry, particularly as levelling, wetting, foaming, dispersing and emulsifying agents, and agents for animalizing vegetable or artificial fibres, i.e. imparting to such fibres an affinity for wool dyes. Examples are given in which (1) triethanolamine hydrochloride and ethylene oxide yield tetraethanol ammonium chloride; (2) triethanolamine sulphate is treated with ethylene oxide; (3) tetraethanol ammonium hydroxide is obtained by the action of barium hydroxide on a product obtained as in example 2; (4) triethanolamine stearate and ethylene oxide yield tetraethanol ammonium stearate; (5) the triethanolamine salt of octadecyl acid sulphuric ester is treated with ethylene oxide to yield the corresponding tetraethanol ammonium salt; (6) trimethylamine hydrochloride and ethylene oxide yield choline hydrochloride; (7) diethylamine sulphate is treated with ethylene oxide and the product is treated with barium hydroxide; diethyl diethanol ammonium hydroxide is obtained; (8) ammonium sulphate is treated as in example 7 to yield tetraethanol ammonium hydroxide; (9) an amine mixture of the formula RN(CH2)3, where R is an alkyl radicle corresponding to the alcohols obtainable by reducing palm-kernel fatty acids, is neutralized with sulphuric acid and treated with ethylene oxide to yield a quaternary ammonium sulphate; (10) pyridine is neutralized with sulphuric acid and treated with ethylene oxide, this yielding ethanol pyridinium sulphate; (11) ammonium chloride is treated with ethylene oxide; (12) morpholine hydrochloride is treated with ethylene oxide; (13) triethanolamine oxalate and ethylene oxide yield tetraethanol ammonium oxalate; (14) triethanolamine formate and ethylene oxide yield tetraethanolammonium formate; (15) ammonium stearate (or monoethanolamine stearate) and ethylene oxide yield tetraethanolammonium stearate; stearic acid glycol ester is obtained as a by-product; (16) a mixture of triethanolamine and a -naphthoic acid is treated with ethylene oxide to yield the tetraethanolammonium salt of a -naphthoic acid and, as a by-product, the glycol ester of the acid.ALSO:Quaternary ammonium salts containing at least one hydroxyalkyl group are obtained by treating an ammonium or amine salt with an alkylene oxide as a raised pressure, the alkylene oxide being taken in about the minimum amount theoretically necessary for the production of a quaternary salt or in a slight excess over that amount; thus, a salt of tertiary amine is treated with one mol. of alkylene oxide, or slightly more, per mol. of amine, while a salt of a secondary amine is treated with two mols. of alkylene oxide, or slightly more, per mol. of amine. The products may be converted into the corresponding quaternary ammonium bases, and both the salts and the bases are useful as emulsifying or dispersing agents. Examples are given in which (1) triethanolamine hydrochloride and ethylene oxide yield tetraethanol ammonium chloride; (2) triethanolamine sulphate is treated with ethylene oxide; (3) tetraethanol ammonium hydroxide is obtained by the action of barium hydroxide on a product obtained as in example 2; (4) triethanolamine stearate and ethylene oxide yield tetraethanol ammonium stearate; (5) the triethanolamine salt of octadecyl acid sulphuric ester is treated with ethylene oxide to yield the corresponding tetraethanol ammonium salt; (6) trimethylamine hydrochloride and ethylene oxide yield chlorine hydrochloride; (7) diethylamine sulphate is treated with ethylene oxide and the product is treated with barium hydroxide; diethyl diethanol ammonium hydroxide is obtained; (8) ammonium sulphate is treated as in example 7 to yield tetraethanol ammonium hydroxide; (9) an amine mixture of the formula RN(CH3)2, where R is an alkyl radicle corresponding to the alcohols obtainable by reducing palm-kernel fatty acids, is neutralized with sulphuric acid and treated with ethylene oxide to yield a quaternary ammonium sulphate; (10) pyridine is neutralized with sulphuric acid and treated with ethylene oxide, this yielding ethanol pyridinium sulphate; (11) ammonium chloride is treated with ethylene oxide; (12) morpholine hydrochloride is treated with ethylene oxide; (13) triethanolamine oxalate and ethylene oxide yield tetraethanol ammonium oxalate; (14) triethanolamine formate and ethylene oxide yield tetraethanolammonium formate; (15) ammonium stearate or monoethanolamine stearate) and ethylene oxide yield tetraethanolammonium stearate; (16) a mixture of triethanolamine and a -naphthoic acid is treated with ethylene oxide to yield the tetraethanolammonium salt of a -naphthoic acid.