The venoconstrictive action of the topical application of Ruscus extract was evaluated in a randomized, double-blind study involving 18 healthy volunteers, using duplex B-scan ultrasonography. Within 2 1/2 hours of the application of 4 to 6 g of a cream containing 64 to 96 mg Ruscus extract, the diameter of the femoral vein decreased by an average (median) of 1.25 mm, while placebo (base of the cream) was associated with a diameter increase of 0.5 mm (means) (p = 0.014). The decrease in venous diameter reflects good percutaneous absorption of the active substance. To date, venoconstrictive action has been demonstrable only indirectly with the aid of plethysmographic methods; it has now been measured directly under orthostatic conditions.