The present invention provides a portable device and method for enhancing blood flow in a limb and for reducing the risk of Deep Vein Thrombosis (DVT) formation by applying periodic squeezing forces on a limb, in particular a lower limb. The device comprises a flask-like casing box and a strap connected to opposite sides of said casing such as to form a closed loop around the limb. Said box contains machinery for actuating periodical change in the circumference of said closed loop between a contracted and a relaxed positions.