Coated sodium percarbonate particles, having an inner shell layer which comprises at least one inorganic, hydrate-forming salt as the main constituent, and an outer shell layer which comprises an alkali metal thiosulfate, an alkaline earth metal thiosulfate and/or an ammonium thiosulfate, are stable to storage and have an improved storage stability in detergents and cleaning agents. Detergents and cleaning agents which comprise such sodium percarbonate particles show a reduced oxidative attack on oxidation-sensitive constituents of the composition during storage. Machine dishwashing agents in the form of tablets which comprise such sodium percarbonate particles and a corrosion protection agent for silver show a reduced yellowing of the tablets during storage.