For a quantitative evaluation of foot or leg volume and its alterations, a new type of instrument is presented. With this apparatus exact results will be achieved in a simple and quick method, which has proved true in several previous investigations. The apparatus is also suitable for the evaluation of therapeutic results concerning swelling of the extremities. This statement is based on measurements of the foot volume of five healthy male volunteers to whom in a double-blind test were administered wto different doses of the active substance ethyl-3,5,6-tri-O-benzyl-D-glucofuranoside (tribenoside, Glyvenol); for comparison also a placebo was used. The dose-response relationship in the foot volume reducing activity of the drug was measured quantitatively. Statistical analysis of the values measured revealed a significant difference at the 1% confidence level between the effects of Glyvenol and placebo on foot volume changes. Further investigations in patients are in preparations.