In a first aspect of the present invention, there is provided a composition comprising 1,2-benzisothiazolin-3-one dispersed in an aqueous medium and further comprising one or more polysaccharide； wherein either (a) said composition comprises no surface-active compound, or (b) said composition comprises one or more surface-active compounds, and the amount of said surface-active compounds in said composition is less than 0.4% by weight based on the weight of said composition.
