The present invention provides aromatic peroxyacids containing at least two peroxyacid groups and a total of at least three peroxyacid or carboxy acid groups, which can be incorporated in detergent or bleaching compositions.The aromatic peroxyacids can be desensitized by intimate contact with a diluent e.g. magnesium sulphate or lauric acid, and coated to reduce destructive interaction with other components of the detergent or bleaching composition. Preferred aromatic peroxyacids include triperoxy trimellitic acid, triperoxy trimesic acid and tetraperoxy pyomellitic acid.The aromatic peroxyacids are especialy suitable for washing white fabrics or cleaning hard surfaces, particularly at a temperature of from 30.degree. to 60.degree. C.