Retrospective analysis of ulcer healing trials utilizing enprostil, a synthetic dehydroprostaglandin E2 analogue, has demonstrated a 10% or greater reduction in total serum cholesterol in 64%, 64% and 67%, respectively, of hypercholesterolemic subjects receiving the drug in doses of 70 micrograms, 35 micrograms, and 7 micrograms bid, respectively. Only 16% of subjects receiving placebo exhibited a similar reduction (P less than 0.05). The median percent changes for hypercholesterolemic patients receiving enprostil 70 micrograms, 35 micrograms, or 7 micrograms bid, and placebo were -17%, -13%, -11%, respectively, while the median percent change for those on placebo was 0% (P less than 0.05). Eight normocholesterolemic subjects participated in a double-blind crossover study comparing enprostil 70 micrograms/d with its placebo. Nine days of enprostil administration was associated with reductions in total serum cholesterol (-16%) and apolipoprotein B (-16%) and with significant reductions from baseline for LDL-cholesterol (-22%), the LDL/HDL-cholesterol ratio (-13%), and the ratio of serum apolipoprotein B to apolipoprotein A-1 (-12%). Relative to placebo, mean HDL-cholesterol, total triglycerides, and apolipoprotein A-1 concentrations remained unchanged. Daily oral administration of microgram quantities of enprostil is associated with reductions in total cholesterol, LDL-cholesterol, and apolipoprotein B suggesting therapeutic potential of this synthetic prostaglandin for the treatment of hyperlipidemia.