Effects of an aqueous extract from Salacia reticulata (SE), which has potent α-glucosidase inhibitory activity, on serum lipid levels in rats were investigated. Serum triglyceride (TG) in rats given a commercial diet containing 0.05 or 0.1% SE for 3 weeks was decreased. SE (0.1%) also suppressed the increase of serum and liver TG, but slightly increased the serum total and HDL-cholesterol (Cho) and liver Cho in rats given a high sucrose diet for 8 weeks. In rats fed a high-Cho diet for 1 week, SE (0.05, 0.1%) had no significant effects on the serum TG and Cho levels, but decreased the liver TG dose-dependently. Moreover, SE had no effect on the serum TG elevation in olive oil-loaded rats. These results confirmed that consecutive ingestion of SE lowered the serum TG level, and this activity appeared to be due to a decrease of absorbed sugars, which are the source of TG in vivo.