The invention relates to a syringe (1) for oral administration of a product, which comprises a body (3) and a tubular piston (5) arranged slidably inside the body (3), said body (3) defining a first chamber (21 ) for receiving the product, the first chamber (21) having at least one vent (29) of product ejection. The body (3) further defines a second chamber (22) extending the first chamber (21). The piston (5) is adapted to sealingly engage with an inner surface (27) of the first chamber (21) with clearance with an inner surface (36) of the second chamber (22).