An antiadhesion membrane made from gellan gum was fabricated and characterized. A 12-µm-thick membrane of gellan gum was prepared and reacted with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide to obtain a cross-linked membrane (G/A70) with 87% gel content and a tensile strength of 46.5 MPa. In vivo, the G/A70 membrane had 90% less tissue adhesion. Inflammation-related and extracellular matrix protein gene expression in a rat model of abdominal surgery was found by real-time quantitative reverse transcription polymerase chain reaction analysis. On day 3, after surgery, the gene expression of ceruloplasmin and type V collagen in the G/A70-treated group was 1.9 and 0.3 times that of the control group, respectively. The G/A70 membrane elicited mild inflammation but suppressed type V collagen synthesis and reduced the occurrence of tissue adhesion. These findings provide insights into the properties of gellan gum antiadhesion membranes and help to overcome problems involving tissue adhesions in surgical procedures.