Pilocarpine HCl has been shown to stimulate parotid and submandibular gland salivary flow. The purpose of this study was to determine whether this cholinergic-muscarinic drug also stimulates labial (minor) salivary gland (LSG) flow and to relate that with whole unstimulated salivary (WUS) flow rates. Subjects diagnosed with primary Sjögren's syndrome (SS-1; n = 9) or secondary Sjögren's syndrome (SS-2; n = 9) were enrolled in this study after meeting stringent enrollment criteria. An age-gender matched control group was also enrolled. The labial saliva was collected in a standardized manner on Periopaper for 5 min and the volume was analysed by the Periotron. Whole unstimulated salivary samples were collected for 5 min by the method of Mandel and Wotman (1976). Each subject was dosed with pilocarpine HCl (5 mg; tablets; p.o.). After 60 min the LSG flow as well as the WUS flow was determined again as previously. The results indicated a significant (> 180%) increase in both labial salivary gland flow as well as whole salivary flow in the SS-1 and SS-2 subjects (mean +/- s.e.m.): [SS-1: WUS = 0.1080 +/- 0.03 vs 0.2242 +/- 0.03 ml per 5 min; LSG = 93.1 +/- 22.2 vs 167.8 +/- 15.9 microliters/5 min; P < 0.001; SS-2: WUS = 0.1384 +/- 0.02 vs 0.2775 +/- 0.09 ml per 5 min; LSG = 97.7 +/- 20.2 vs 182.8 +/- 17.9 microliters per 5 min; P < 0.001]. These results indicate a significant increase in labial salivary gland flow as well as whole salivary flow as stimulated by pilocarpine HCl in Sjögren's syndrome patients.