Black Cohosh extract is a form of phytoestrogen (estrogen of plant origin) that is effective in controlling bothersome hot flushes, while avoiding the dangers of using hormones. Recent case reports pointed to potential toxicity of black cohosh on the liver. The investigators are trying to verify or refute such allegations.

The aim of this prospective longitudinal clinical trial is to evaluate changes in total hepatic blood flow and liver functions among postmenopausal women using black cohosh (cimicifuga racemosa) extract for twelve consecutive months for relief of vasomotor symptoms.

Prior to using a daily dose of 40 mg of a dry extract preparation of cimicifuga racemosa (Klimadynon®) and twelve months after, total hepatic blood flow will be assessed by color Doppler ultrasound. Moreover, prothrombin time & concentration, serum albumin, bilirubin, gamma-glutamyl transferase (GGT), alkaline phosphatase (ALP), alanine aminotransferase (ALT) and aspartate aminotransferase (AST) will also be measured.

Inclusion Criteria:

• an age over 40 years
• with a lapse of one year after the last menstruation
• symptomatic women without gynecological illness
• after naturally occurring menopause
• had never used hormonal therapy or had stopped using them for >6 months
• accepting to participate after receiving adequate description of the study
• accessible for regular follow-up.

Exclusion Criteria:

• vaginal bleeding
• active or chronic liver disease and /or abnormal liver functions
• present or past thromboembolic disease
• present or past neoplasia of the breast or uterus
• an endometrial thickness >5 mm by TVS
• use of alternative or complementary medicines or herbs for menopausal symptoms within the previous three months