Introduction: Certain fermented dairy milk products may have bene®cial effects on plasma cholesterol levels. However, a number of studies have produced con¯icting results as to whether dietary supplementation by a probiotic dairy product containing the bacteria culture Causido 1 reduces plasma cholesterol. Objective: To conduct a meta-analysis of intervention studies to evaluate the effect of the Causido 1 culture on plasma total cholesterol and low-density lipoprotein (LDL)-cholesterol. The probiotic milk product: The yoghurt product Gaio 1 is fermented with Causido 1 , composed of one strain of Enterococcus faecium (human species) with the proposed cholesterol-lowering effect, and two strains of Streptococcus thermophilus. Study inclusion and data extraction: Six studies were identi®ed from a literature search and from the yoghurt producer. All studies met the inclusion criteria. Summary data for plasma concentrations of total cholesterol and LDL-cholesterol were extracted from the original publications or by personal request to the authors. Data from 4 ± 8 weeks of treatment duration was used. Statistical analysis: We performed a traditional meta-analysis where mean differences between intervention and control of the pre ± post changes in total cholesterol and LDL-cholesterol were calculated, as well as 95% con®dence intervals (CIs). Results: In the six studies included in the meta-analysis, the Gaio 1 interventions produced changes in total cholesterol above those of the control groups ranging from À0.02 to À1.02 mmolal and in LDL-cholesterol ranging from À0.02 to À1.15 mmolal. After inclusion of an open-label study, the meta-analysis of the doubleblind studies showed that Gaio 1 as compared to the control group changed total cholesterol by À0.22 mmolal (95% CI: À0.35 to À0.08, P`0.01) and LDL-cholesterol by À0.20 mmolal (95% CI: À0.33 to À0.06, P`0.005). The outcome was essentially the same if all studies were included. Conclusions: The present meta-analysis of controlled short-term intervention studies shows that the fermented yoghurt product produced a 4% decrease in total cholesterol and a 5% decrease in LDL-cholesterol when the open-label study is excluded. To demonstrate sustained effects on blood lipids, long-term studies are required. Sponsorship: MD Foods AaS, Denmark. Descriptors: probiotic milk product; plasma cholesterol; meta-analysis