The effects of dietary intake of sucrose versus the use of sodium cyclamate were studied in 10 Type 1 (insulin-dependent) diabetic patients on continuous subcutaneous insulin infusion therapy. After a 4-week run-in period, the patients were randomly assigned to a cross-over protocol with two 4-week periods during which they used sucrose or sodium-cyclamate as sweetener. During the experimental periods, 24 +/- 13 g/day sucrose and 348 +/- 270 mg/day of sodium cyclamate were consumed, respectively. Metabolic control was monitored by the patients performing blood glucose self-monitoring several times daily. Bi-weekly, all patients were followed-up in our outpatient clinic. Mean daily blood glucose concentrations as well as the average daily insulin dose did not differ between the three experimental periods. HbA1c-levels, serum lipids and body weight remained unchanged and within the normal ranges throughout the study. Thus, moderate dietary intake of sucrose did not affect metabolic control in these normal weight, near-normoglycaemic, normolipidaemic, pump-treated Type 1 diabetic patients during a 1-month period. Whether similar conclusions apply to less well controlled diabetic patients remains to be seen.