Colestipol is an effective cholesterol (C)-lowering agent, but it must be taken in large doses and the palatability is poor. In an open-label study, the effects of low doses (2-10 g) of encapsulated colestipol (size: 1 g or 0.65 g) were investigated. There were 16 men and 16 women with an average age of 59 +/- 11 years and with hyperlipidemias IIA, IIB, or IV. Patients were on AHA I diet and stayed in the study for up to 2 years with regular follow-up every 3 to 4 months. Colestipol was started after several months of dietary baseline; it was tolerated well with only two patients reporting mild constipation. A group mean for total cholesterol (T-C), LDL-C, HDL-C, VLDL-C and triglycerides (TG) was calculated at each of four daily dose intervals, i.e., 2 to 4 g, 4 to 6 g, 6 to 8 g and 8 to 10 g. Each patient usually received more than one of the four dosage intervals. A paired t test and a rank sum test were performed to test for significant (P less than or equal to .05) differences between baseline and drug treatment. With the exception of the lowest dose, total C was significantly decreased by all dosage ranges and LDL-C changes were similar. There was no significant effect on HDL-C and VLDL-C whereas TG levels increased at 4 to 6 g and 8 to 10 g dose. The use of diet and low colestipol doses may be considered in patients with moderate hypercholesterolemia who do not respond to diet alone.