Angelica gigas Nakai, Korean dang-gui, has long been widely used in traditional treatment methods. There have been a number of studies of the health effects of A. gigas and related compounds, but studies addressing effects on blood triglycerides (TG) are lacking. To investigate the effects of A. gigas Nakai extract (AGNE) on TG in Korean subjects, we carried out a 12-week, randomized, double-blind, placebo-controlled clinical trial. Subjects who met the inclusion criterion (130 mg/dL ≤ fasting blood TG ≤ 200 mg/dL) were recruited for this study. One hundred subjects were assigned to the AGNE group (n = 50) or the placebo group (n = 50), who were given 1 g/day of AGNE (as a gigas Nakai extract 200 mg/d) in capsules and the control group for 12 weeks. Outcomes were efficacy TG, lipid profiles, atherogenic index, and safety parameters were assessed initially for a baseline measurement and after 12 weeks. After 12 weeks of supplementation, TG and very low-density lipoprotein cholesterol (VLDL-C) concentration and TG/HDL-C ratio in the AGNE group were significantly reduced compared to the placebo group (p < 05). No significant changes in any safety parameter were observed. These results suggest that the ingestion of AGNE may improve TG and be useful to manage or prevent hypertriglyceridemia.