Antiadhesive barrier solution (AABS) has been proven to prevent intraabdominal adhesion by reducing inflammation and fibrosis formation. Because this mechanism can also be applied to capsule formation after the breast implant insertion, we hypothesize that AABS can reduce capsular contraction and evaluate the efficacy of AABS on perisilastic implant capsule formation after submuscular insertion. A silicone block was inserted beneath the panniculus carnosus muscle in 10 rats. The experiment group received 0.1 mL of AABS (Guardix, Hanmi Medical Co.) instilled into the pocket, whereas the control group received 0.1 mL saline solution. Periimplant capsules were excised after 4 weeks and were evaluated for inflammatory cell count, capsular thickness, collagen pattern, and amount of myofibroblast. The inflammatory cell count and the capsular thickness were lower in the experiment group than in the control group (P < 0.05). The collagen pattern was loose and parallel in the experiment group, and the amount of myofibroblast was much less compared with the control group. AABS reduced the amount of inflammatory cells, myofibroblast, and capsular thickness. It also made the collagen fibers in the capsule loose and parallel. Therefore, AABS seemed to be effective in reducing the periimplant capsule formation.