The invention relates to microbicidal preparations which comprise a) at least one of 1,2-benzisothiazolin-3-one and its derivatives, b) at least one of 2-mercaptopyridine N-oxide, its salts and derivatives, c) at least one aromatic alcohol and d) at least one alkalinizing agent, or which are prepared by mixing components a) to d), where the preparations have a pH of at least 11. The preparations are characterized by the fact that they are clear and storage-stable, and they are suitable for use as preservatives.
