Many reports show (DAVIDOFF 1973, HOOK et al. 1970, KOSTULAK 1974, MILSOM 1970, THYBERG 1972) that arylsulphatases are widely present in the tissues of many animals, and a high activity has been observed, among other things, in secretory epithelia (HSU and TAPPEL 1965, KOSTULAK 1975, MAKITA and SANBORN 1971). The occurrence of these enzymes some authors connect with the metabolism of sulphated polysaccharides (DOGSON 1968, MARTIN et al. 1969, MEYER 1969). However, although the specificity and intracellular localization of these enzymes in different tissues have been described perviously, there are only a few reports about their localization in the salivary gland, and the functional role of arylsulphatases in the physiological function of the salivary glands. The observations reported by numerous authors (KOZLOWSKA 1973, KYAW and MELLORS 1972, SACHS and DE DUVE 1962), and in ours studies (KOSTULAK 1975) indicate that the activity of lysosomal enzymes, including arylsulphatases, is modified by steroid hormones. Moreover, it is known that these hormones have an influence on the composition and nature of the carbohydrate-protein complexes produced by the salivary glands (KOFOED et al. 1973, KOSTULAK et al. 1972). Therefore it seemed interesting to examine the behaviour of arylsolphatases in the salivary glands after treatment with large doses of ACTH and cortisone, and find if there is any correlation between the activity of these enzymes and the changes of sulphated polysaccharides observed previously in the cell of the salivary glands after applying ACTH and cortisone.