Four patients, three women and one man, with a mean age of 32 years, presented with a history of recurrent parotid swelling. In the women the swelling was unilateral. All had previously undergone sialography using a hand injection technique and no structural abnormality was demonstrated. Sialography was repeated using a continuous-infusion pressure-monitored system. In all cases an initial very high filling pressure (>200 mmHg) was recorded followed by a rapid reduction in pressure and a more normal filling pressure pattern. The duct system and glands all appeared morphologically normal. Treatment with acrylic appliance therapy and an intraductal catheter was attempted with some success.