Unhealthy lifestyle and environmental factors may influence semen parameters via oxidative stress, functional hypogonadism and xenobiotics. The aim of the study was to evaluate the influence of a diet supplement containing glutathione and herbs with antioxidative and antioestrogenic activity, in combination with lifestyle improvement, on semen parameters. Data from the medical records of 50 men aged 24-52 (median 35.0) with idiopathic abnormalities in semen parameters were retrospectively analysed. The inclusion criteria comprised sperm concentration >5 mln/ml, disorders in sperm motility and/or vitality and/or morphology, good general health, no present nor previous diseases or treatment which may influence fertility, and normal testicular volume. Patients were advised to change their lifestyle and take the supplement for three months. Basic semen analysis and serum FSH, LH and testosterone levels were performed before and after the prescribed therapy. After three months of treatment, median serum concentrations of FSH significantly increased by 70%, LH by 67% and testosterone by 79%, and all mean semen parameters were significantly increased (total sperm count by 68%). It seems that lifestyle changes supported by consumption of herbs with antioxidative and antioestrogenic activity may be suitable for the first-line therapy for patients with mild idiopathic abnormalities in semen parameters or serum concentrations of reproductive hormones.