We explored the connection between varicose vein and edema, by investigating extracellular water ratio (E/T) using bioelectrical impedance analysis. In a prospective cohort study 120 patients underwent varicose vein surgery with extracellular fluid to total body water ratio (E/T) and E/T postop divided by E/Tpreop (E/T ratio) measured using a body composition analyzer. Edema was defined as E/T ≥0.390. Seventy-nine patients received unilateral treatment, while 41 underwent bilateral. p < .05 is statistically significant. Preoperatively, patients exhibited edema (E/T) in the treated leg (0.394 ± 0.009), untreated leg (0.392 ± 0.009), trunk (0.390 ± 0.007), and whole body (0.391 ± 0.007). Postoperatively, E/T decreased across body (p < .05). The lowest E/T ratio was observed in the treated leg (0.991 ± 0.012), followed by the untreated leg (0.994 ± 0.012), the trunk (0.995 ± 0.009), and the whole body (0.994 ± 0.009). E/T ratio of bilateral group were lower than unilateral group (p < .05). Varicose vein contributes to generalized edema, and treatment alleviates edema in the treated leg and the entire body.