The effect of the three-monthly injectable contraceptive depot medroxyprogesterone acetate (DMPA) on liver and lipid function was assessed in Thai women with liver fluke (Opisthorchis viverrini) infestation, DMPA administration being started in the immediate postpartum period. Immediate postpartum IUD and sterilization acceptors with fluke infestation were recruited as a comparison (control) group for the fluke-positiv DMPA acceptors. Comparable groups of fluke-negative acceptors were recruited in an area of Thailand free of liver fluke transmission. Results are presented for the first 6 follow-up months for 170 DMPA and 177 control fluke-positive subjects and for 153 DMPA and 150 control fluke-negative subjects. Small and similar increases occurred in each of the four groups for alanine amino transferase, isocitrate dehydrogenase, and total bilirubin levels while aspartate amino transferase levels changed less in the DMPA groups than in their respective control groups. None of the subjects in either DMPA group had clearly abnormal results in these tests at 6 months. Alkaline phosphatase, cholesterol, and triglycerides levels were markedly lower in each group at 6 months than in the puerperal specimens. There was a greater decrease in triglycerides levels in both DMPA groups than in their respective control groups. However, the decrease in the alkaline phosphatase and cholesterol levels was greater only in the fluke-positive DMPA group than in the fluke-positive control group. None of these biochemical results were related to differences in age, parity, or lactation status between the groups. The results indicate that DMPA did not cause any early deleterious effects in the metabolic factors studied in women with liver fluke infestation.