The combination of silver or silver with isothiazoline gives a new and very effective preservative system. By using this combination, the amount of sensitizing isothiazoline can be significantly reduced and, if an excess of benzisothiazoline is used, the well-known photosensitivity of silver compounds is reduced. This combination is a highly effective and safe new preservative system for coatings. Labeling limits such as R43 for "sensitization" and N for "dangerous for the environment," and pressures to choose from positive lists like the Blue Angel, are reducing the choice and applications of the existing biocides. Additionally, numerous preservatives will no longer be available once the Biocidal Products Directive comes into force and regulatory pressure continues to lower the limits for the labeling of single preservatives. Existing combinations of known actives have already reached their limits, and further novel optimization is unrealistic.The germicidal activity of silver has been known since ancient times.