This clinical trial is a multi-center, double-blind, randomized, active controlled , parallel design, non-inferiority phase 4 study to evaluate the efficacy and safety of Entelon 150mg in 278 patients with chronic venous disease.

This study is to prove that Entelon tab. 150mg is non-inferior in clinical efficacy and safety compared to Venitol tab. for 8 weeks in patients suffering from chronic venous disease.

Inclusion Criteria:

1. 19 years ≤ age ≤ 80 years

2. Those who are diagnosed as CEAP Classification Class 1 ~ Class 3

3. Those who have the Venous Duplex ultrasonography result at least one of the following

   • reflux more than 1 second in Femoral vein or Popliteal vein
   • reflux more that 0.5 second in GSV or SSV or Accessory saphenous vein or perforating vein or calf vein

4. Those who have completed the washout period as following until the baseline, including the screening period

   • Analgesic, corticosteroids, anti-inflammatory drugs: at least 2 weeks

5. Those who provide written consent voluntarily to participate in this clinical trial

Exclusion Criteria:

1. Those who must wear compression stockings
2. Those who have obstruction of the peripheral arteries of the lower extremities
3. Those who have asymptomatic varicose veins
4. Those who have acute deep vein thrombosis
5. Those who have frequent lower extremity pain due to neuropathy
6. Varicose vein surgery patient or prospective person (if surgery was done more than 1 year prior to the time of screening, recruitment is possible)
7. Those who have systemic disease that causes edema or thrombosis
8. Those who have a history of malignant tumors within 5 years prior to the time of screening
9. Those who have severe renal dysfunction at the time of screening (serum creatinine ≥ 2 x upper limit of normal)
10. Those who have severe liver dysfunction at the time of screening (AST or ALT ≥ 3 x upper limit of normal)
11. Those who are required to receive diuretics, analgesics, corticosteroids, anti-inflammatory drugs, or contraindications that may affect the outcome of this clinical trial during the clinical trial period
12. Those who have a history of significant mental illness, alcohol abuse
13. Patients who have an allergy to investigational product or any of its excipients
14. Patients who participated in other clinical trials within 12 weeks prior to the date of screening
15. Pregnant or lactating woman
16. Those who do not agree to use an effective method of contraception
17. Individual considered by the investigator to be ineligible for study participation