Abstract: A method for the gasification of large-sized vegetable materials using a ed bed gasogene. This gasification method includes the steps of moving the materials in a fixed treatment chamber extending substantially horizontally and having opposite rear and forward ends, the materials being moved from the rear end towards the forward end through substantially the whole transverse section of the chamber and being successfully subjected to drying, pyrolysis and gasification in successive areas of the chamber. Hot gases are generated by combustion in a zone free of materials to be treated and located in the chamber in front of the natural talus created by the front of the whole bulk of materials which occupy substantially the whole transverse section of the chamber. Gases are extracted from the chamber and recycled into the zone in front of the natural talus, whereby tar produced from the pyrolysis and carried away by the extracted gases is eliminated by heating the recycled gases in the zone.