Sitting for a long time appear swollen feet, there are three main reasons: the first point, lower limb venous return obstruction, long-term sitting caused by muscle no movement, venous function disappeared, coupled with the veins without valves, venous blood can not be refluxed, the accumulation in the local area, resulting in the formation of intravascular fluid extravasation of oedema; the second point, long-term sitting slowed down the flow of venous blood, easy to form the lower limbs of the deep venous thrombosis, caused by venous reflux obstruction, oedema of the lower extremities; the third point, to exclude the lower limbs of the oedema caused by renal diseases, renal insufficiency, but also to exclude the cirrhosis of the liver, hepatitis, and other liver diseases caused by liver insufficiency, resulting in hypovitaminosis and the emergence of the lower limbs of the oedema.