Abstract: AIM To evaluate the feasibility, safety of a fully biodegradable occluder for closure of patent foramen ovale (PFO) in an acute canine model. METHODS The PFO was created in healthy canine by a homemade PFO perforator and the PFO was closed immediately by the fully biodegradable PFO occluder. Animals were sacrificed at 1, 3, 6, 9 and 12 months after procedure. RESULTS Acute PFO models were successfully created in 10 dogs and occluders was successfully implanted in the PFO model. The cardiac gross anatomy revealed that all occluders were stable in the fossa ovale and no vegetation or thrombosis formation was observed on the surface of all occluders. The endothelial tissue gradually covered from the edge of the surface of occluder. Different periods of pathological observations suggested that the skeleton of occluder is almost completely degraded and integrated with the host tissue at 6 month follow-up. CONCLUSION The present investigation applied fully biodegradable occluder to close PFO in a canine model and no residue was identified in the body after degradation.This is a safe, effective and feasible method of closing the PFO and the efficacy was similar when compared to a metal occluder.