An endoscopic instrument adapted to engage the stomach tissue and/or the esophagus tissue of a patient from the inside and/or outside thereof, the esophagus being a substantially tube shaped tissue leading to the stomach comprising stomach tissue, the esophagus having an esophagus center axis, being substantially aligned with a cranial-caudal axis of the patient and having a substantially circular circumference substantially aligned with a horizontal plane of the patient, the esophagus further having an inner and outer substantially cylindrical surface extending radially in relation to the esophagus center axis, wherein said instrument is adapted to deliver at least one fixating member (14, 14a,b), such that said at least one fixating member (14, 14a,b) engages at least the stomach tissue, the endoscopic instrument comprising a first and a second operable joint configured to allow said instrument to go around the angle of His and reach the fundus area of the stomach characterized in that said instrument comprises: a first and a second part (1005a,b) adapted to engage said at least one fixating member (14, 14a,b); the first and second parts (1005a,b) being separated by at least the first and second operable joints such that the first and second parts can deliver said at least one fixating member (14, 14a,b) between themselves and such that esophagus tissue and stomach tissue is placed between the first and second parts (1005a,b) when positioned to engage said at least one fixating member (14,14a,b); and a pulling member configured to pull or grab stomach tissue and hold said stomach tissue in position for delivery of said at least one fixating member (14, 14a,b); wherein at least one of the first and second parts (1005a,b) is configured to deliver said at least one fixating member (14, 14a,b) adapted to penetrate at least two layers of stomach tissue, or at least one layer of stomach tissue and one layer of esophagus tissue, thereby creating a pouch of stomach tissue, and the other of the first and second parts (1005a,b) is configured to function as an anvil member to assist in the fixation of said at least one fixating member (14, 14a,b). a first and a second part (1005a,b) adapted to engage said at least one fixating member (14, 14a,b); the first and second parts (1005a,b) being separated by at least the first and second operable joints such that the first and second parts can deliver said at least one fixating member (14, 14a,b) between themselves and such that esophagus tissue and stomach tissue is placed between the first and second parts (1005a,b) when positioned to engage said at least one fixating member (14,14a,b); and a pulling member configured to pull or grab stomach tissue and hold said stomach tissue in position for delivery of said at least one fixating member (14, 14a,b); wherein at least one of the first and second parts (1005a,b) is configured to deliver said at least one fixating member (14, 14a,b) adapted to penetrate at least two layers of stomach tissue, or at least one layer of stomach tissue and one layer of esophagus tissue, thereby creating a pouch of stomach tissue, and the other of the first and second parts (1005a,b) is configured to function as an anvil member to assist in the fixation of said at least one fixating member (14, 14a,b). <EOS>