Tamoxifen, a non-steroidal anti-estrogen is now widely used and has led to an increase in both disease-free and overall survival of women after primary surgery. Tamoxifen therapy is found to cause hypertriglyceridemia by reducing activity of lipolytic enzymes on triglycerides, and thereby increasing the risk of cardiovascular disease. Angiogenesis promotes local tumour progression and invasion and enables tumour cell dissemination and metastasis formation. Our study has found that co-administration of Coenzyme Q10 (100 mg) along with tamoxifen (10 mg, twice a day) to breast cancer patients reduced the level of angiogenesis markers and lipid levels.