Norplant subcutaneous implantation is a contraceptive method used in Indonesia. Endometrial bleeding is one major reason to discontinue the use of Norplant. Angiogenic response in the endometrium of Norplant users was found to be lower than in women with normal menstrual cycle. This disturbance in the angiogenic process may be caused by an imbalance of pro- and antioxidant processes in the endometrium of Norplant users. The aim of this study is to investigate the effect of vitamin E on the endometrial angiogenic activity and to assess the efficacy of vitamin E supplementation in treating endometrial bleeding in Norplant users. Subjects for this study were selected from Norplant users with an exposure of at least 3 months, with endometrial bleeding and recruited on the basis of fully informed consent. TBA reaction was used to measure degradation products of lipid peroxidation. The endometrial angiogenic response was assayed according to Folkman et al. (Folkman et al., 1989. Nature 239, 58-61). Samples from endometrial biopsies were incubated in vitro with vitamin E or placebo before angiogenic measurement. For in vivo supplementation, vitamin E 200 mg/day, or placebo for 10 days/month were given to the subjects with double blind randomisation. The results showed that the blood levels of TBA-reactive substances were significantly higher in Norplant users than in controls. In the endometrium from Norplant users with bleeding problems, in vitro supplementation of vitamin E resulted in a significantly higher angiogenic score than placebo. Although a highly significant reduction of bleeding days in both groups, vitamin E and placebo, was seen during the 2 months of the study, the number of bleeding days was significantly lower in women treated with vitamin E than with placebo.