The sensitivity of the rat parotid gland to chemical agents was examined 2–3 weeks after either parasympathetic denervation or sympathetic denervation or decentralization. The parasympathetically denervated gland was markedly sensitized towards methacholine; a nonspecific supersensitivity mainly mediated via α-adrenoceptors was also demonstrated. The sympathetically denervated gland had developed a supersensitivity which was both of the pre-and the postjunctional type; it was predominantly of the former type to noradrena-line and adrenaline, and entirely so to phenylephrine; it was of the latter type to isoprene-line, and also to methacholine. The sympathetically decentralized gland was mainly sensitized towards noradrenaline, adrenaline and isoprenaline. The postjunctional super-sensitivity developed towards the sympathomimetic drugs after sympathetic decentralization was of about the same magnitude as that observed after sympathetic denervation; this type of supersensitivity was mainly mediated via β-adrenoceptors.