A method for non-invasively measuring a physiological parameter of a subject, comprising: applying to a body part of the subject a venous occlusion plethysmographic device (10, 30) including a first section having a first fluid chamber (C 1) to engage a first region of the body part, and a second section having an at least second fluid chamber (C 2) to engage a second region of the body part proximally located to said first region at the side thereof facing the heart of the subject; said engaged regions being so-engaged throughout a respective extent of each; pressurizing said first (C 1) and at least second fluid chambers (C 2); measuring changes in volume of said first region of the body part; and utilizing said measured changes in volume to provide a measure of said physiological parameter; said first fluid chamber (C 1) being pressurized to a pressure level exceeding the sum of the inherent venous pressure and the hydrostatic pressure prevailing within said body part; characterized in that a pressure in said at least second fluid chamber (C 2) being intermittently raised to and lowered from a pressure above or equal to the pressure within said first fluid chamber but below the arterial blood pressure; such that the measured changes in volume in said first region of the body part are a measurement of changes in the accumulated blood volume therein, which changes are utilized to provide a measurement of said physiological parameter; said engaged second region is adjacent to said engaged first region, and said engaged first region comprises the distal tip of said body part, such that hydrostatic pressure due to said body part being at a low vertical level with respect to heart level is counterbalanced in said body part distal to said second region, when said first region is so-pressurized, and such that induction of venous distension distal to said second region is avoided. applying to a body part of the subject a venous occlusion plethysmographic device (10, 30) including a first section having a first fluid chamber (C 1) to engage a first region of the body part, and a second section having an at least second fluid chamber (C 2) to engage a second region of the body part proximally located to said first region at the side thereof facing the heart of the subject; said engaged regions being so-engaged throughout a respective extent of each; pressurizing said first (C 1) and at least second fluid chambers (C 2); measuring changes in volume of said first region of the body part; and utilizing said measured changes in volume to provide a measure of said physiological parameter; said first fluid chamber (C 1) being pressurized to a pressure level exceeding the sum of the inherent venous pressure and the hydrostatic pressure prevailing within said body part; characterized in that a pressure in said at least second fluid chamber (C 2) being intermittently raised to and lowered from a pressure above or equal to the pressure within said first fluid chamber but below the arterial blood pressure; such that the measured changes in volume in said first region of the body part are a measurement of changes in the accumulated blood volume therein, which changes are utilized to provide a measurement of said physiological parameter; said engaged second region is adjacent to said engaged first region, and said engaged first region comprises the distal tip of said body part, such that hydrostatic pressure due to said body part being at a low vertical level with respect to heart level is counterbalanced in said body part distal to said second region, when said first region is so-pressurized, and such that induction of venous distension distal to said second region is avoided.