In this primary article, the author mainly investigates the effectiveness of coenzyme q10 on coronary heart disease. The author conducts a matched control group, with 64 patients who have coronary artery disease compared to 34 healthy individuals. Plasma coenzyme Q10 concentrations with respect to low-density lipoprotein (LDL), triglyceride (TG) and total cholesterol (TC) content were measured in both groups and are statistically analyzed to test the relationship of coenzyme Q10. The results found a significant high amount of TC, LDL and TG values, and a low HDL value in patients with cardiovascular diseases compared to healthy groups. In addition, a lower coenzyme Q10 concentrations per TC, LDL and TG is also presented. Based on these results, it is clear that the plasma coenzyme Q10 have a strong protection against cardiovascular disease, due to its antioxidant activity, which acts a marker of oxidative stress in the early stage of coronary artery disease. The data in this paper is highly reliable but not very informational. This study only contains one experiment with limited experimental group that lowers the significance of the result. Conflicting results experimented by Hanaki et al mentioned in this article show lower plasma coenzyme Q10 concentration in normal healthy group, which suggests that there might be other factors correlate to cardiovascular disease. Overall, the author in this paper states that this correlation they found between coenzyme Q10 and cardiovascular disease does not directly indicate a causal relationship, thus further investigations with specific design is needed to determine whether such causal relationship exists. The author in this review mainly summarizes the deficiency of coenzyme Q10 in various cardiovascular diseases such as coronary artery disease, congestive heart failure etc., and its clinical utility on preventing and treating those diseases. Despite the function of Coenzyme Q10 as an endogenous antioxidant supplement that protect low density lipoprotein against oxidation of lipid peroxide free radicals, it is also used to treat cancer and other conditions. Such property of Coenzyme Q10 suggests that it may be very effective to prevent heart diseases. This comprehensive review not only points out numerous findings on the deficiency of coenzyme Q10 in various diseases, but also evaluates coenzyme Q10 as therapeutic supplement that potentially increases serum and myocardial levels in cardiovascular patients. One study mentioned in this review written by Folkers et al, the author concludes that a supplement of 100 mg/day of Coenzyme Q10 for 2-8 months increases 20%-85% of myocardial levels in coenzyme Q10 deficiency patients, which makes an important step for clinical uses to treat such disease. Moreover, animal studies are presented in this paper that uses mostly dogs which are given small dosse of coenzyme q10 before they are experimentally induced with ischemia and myocardial infarction. Results in those animal studies show a significant reduce in severe cell degeneration and increase in the recovery of myocardial energy consumption. Such study is very meaningful which provides basic knowledge of the effectiveness of coenzyme q10 despite human cellular system are different from animals. In comparison, little human studies have been conducted, but most of those studies that are conducted on humans shows magnificent efficiency of coenzyme Q10 as a routine supplement that enhances cardiovascular health. Overall, this review is highly informational. Further experiments are needed to provide stronger evidence of Coenzyme Q10 as a recommendation to treat cardiovascular diseases.In this article, the author mainly investigates the use of coenzyme Q10 on oxidative stress and antioxidant enzyme activity to prevent cardiovascular disease (CVD). This is a randomized, parallel, placebo-controlled study, in which 59 patients identified by CVD are randomly assigned to placebo group, Q10-60 group and Q10-150 group. Plasma malondialdehyde (MDA), glutathione peroxidase (GPx), catalase (CAT), superoxide dismutase (SOD), along with coenzyme Q10 concentration in blood was measured and statistically analyzed into 5 histograms associated with time in x-axis. The result shows an increased coenzyme Q10 concentration at week 4, 8 and 12 in both Q10-60 and Q10-150 group, as Q10-150 group increases more significantly. The MDA levels of both experimental groups are lower than the placebo group, compared with the antioxidant activity, in which there is an increased level of CAT and SOD in both experimental groups, especially higher increase in Q10-150 group, but little significance is found in GPx activity. In addition, there is a significant correlation of coenzyme Q10 concentration with MDA, CAT, and SOD activity, the same as the ratio of coenzyme Q10 with respect to either total cholesterol or low-density lipoprotein, but zero correlation of all cases above with GPx activity. Although this paper has limitations of experimental subjects and the number of controls, the data is still reliable. Based on these results, it is clear that coenzyme Q10 plays an important role against cardiovascular disease, attributed by its antioxidant function. With a decrease in MDA activity indicates decreased free-radical damage, and an increase in both CAT and SOD activity indicates increased protection of cell against oxidative stress, all shows the importance of coenzyme Q10 as a useful supplement. With a higher dosage of coenzyme Q10 concentration for patients with cardiovascular disease, it might absorb and sustain antioxidation more effectively.