The aim of this clinical study was to compare the degree of postoperative pain (VAS--10 cm, quality of life questionnaire CIVIQ and patient diary) between two groups of patients: patients treated with Detralex 14 days before and 14 days after the stripping of greater saphenous vein (GSV) and patients not treated with Detralex. In addition, the two groups were also compared for the incidence of symptoms associated with chronic venous insufficiency (CVI) (using the VAS scale: edema, tired and heavy legs, cramps, itching sensation), size of hematoma, use of analgesics and overall efficacy of the treatment. Clinical study included 181 patients from 15 medical centers throughout the Czech Republic. High ligation and partial stripping of greater saphenous vein on one lower extremity was performed in all patients (short stripping from groin to knee). Patients were randomly assigned in two groups: patients treated with Detralex (92) and patients not treated with Detralex (89). Patients in the first group were treated with Detralex for the period of 1 month. Degree of pain and patient's health condition were evaluated by the physician during D-14 (14 days prior to the surgery), D7 and D14 (7 and 14 days after the surgery) visits using the 10-cm visual analog scale VAS. The results indicate that Detralex reduced the intensity of postoperative pain, which resulted in decreased consumption of analgesics. Hematoma was smaller in patients already using Detralex 14 days prior to the scheduled stripping procedure. These patients also showed significant improvement of CVI symptoms and the quality of life of patients with CVI. High quality venoactive drugs administered 14 days prior to the surgery improve postoperative course in patients indicated for surgical treatment of varices.