We investigated the influence of the streptozocin (STZ)-diabetic state on the dose-response curves for salivary flow and protein content in saliva stimulated by pilocarpine and noradrenaline in mice. The diabetic state increased the relative weights of parotid and sublingual salivary glands but not the weight of submandibular glands, despite body weight loss. In the dose-response curves, (1) the maximal responses to stimulation with pilocarpine and noradrenaline on salivary flow, and with noradrenaline on protein content in saliva, were depressed by the diabetic state, and (2) the value of the 50% effective dose for salivary flow with pilocarpine, but not with noradrenaline, was decreasingly altered by diabetic mice. These results suggest that xerostomia, one of the complications of non-insulin-dependent diabetes mellitus, is caused in part by muscarinic and adrenergic receptor dysfunction in the salivary glands.