Metabolic syndrome (syndrome X) causes millions of cardiovascular complications and premature deaths every year. The aim of this study was to evaluate the effects of NeOpuntia®, patented, dehydrated,Opuntia ficus-indica leaves, on blood lipid parameters and metabolic syndrome.Opuntia ficus-indica leaves are traditionally consumed as a vegetable. Participants in this monocentric, randomized, placebo-controlled, double-blind, 6-wk study were 68 women, ages 20 to 55 y, with metabolic syndrome and a body mass index between 25 and 40. Fifty-nine subjects completed the study according to the study plan. All volunteers followed well-balanced diets with controlled lipid input. NeOpuntia or placebo capsules were taken at a dosage of 1.6 g per meal. All 5 syndrome X criteria were measured on days 0, 14, and 42, including low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and triglyceride levels. For the 42 females above 45 y of age, we show a significant increase in HDL-C levels with NeOpuntia and a tendency toward decreased triglyceride levels. At the same time, there was a decrease in HDL-C levels with placebo. Overall, for the entire study population, similar but less pronounced tendencies were demonstrated. Forty-two females taking NeOpuntia with no additional hypolipemic treatment, had a pronounced reduction in LDL cholesterol, especially after day 14. At the study end, 39% of the NeOpuntia group, but only 8% of the placebo group, were no longer diagnosed with metabolic syndrome. Our results indicate an advantage of using NeOpuntia in dietary supplements and functional foods because of improvement of blood lipid parameters associated with cardiovascular risks.