The use of polymers containing .beta.-hydroxyalkylvinylamine units, as obtainable by reacting polymers containing vinylamine units with epoxides of the formula ##STR1## in which R is C.sub.2 -C.sub.28 alkyl, phenyl, C.sub.1 -C.sub.18 alkylphenyl or C.sub.2 -C.sub.18 alkenyl, as biocides.

El uso de los polímeros que contienen unidades del beta.-hydroxyalkylvinylamine, como obtenibles reaccionando los polímeros que contienen unidades del vinylamine con los epoxides del ## del ## STR1 del fórmula en el cual R es C.sub.2 - C.sub.28 alkyl, fenilo, C.sub.1 - el alkylphenyl C.sub.18 o C.sub.2 - alkenyl C.sub.18, como biocides.