A device for treating acid reflux comprises a sleeve (10, 10', 30, 44, 50, 60, 70, 80, 85, 90, 102, 105, 110, 120, 130, 150, 160) configured and dimensioned for insertion into the esophagus (2) of a patient, the sleeve having a proximal portion (14, 14', 34), a distal portion (12, 12', 32) and an intermediate portion (33) between the distal and proximal portions. The sleeve includes an inner member (16, 20, 20', 36, 45, 47, 51, 65, 71) applying a radial force on the sleeve for securement within the esophagus, and a skirt (22, 22', 42, 48, 55, 61, 75, 92, 103, 106, 112, 122, 132, 142, 152, 162) connected to the sleeve to block acid backup from the stomach while not inhibiting passage of food into the stomach.
