Fuel injector of an internal combustion engine and internal combustion engine

A fuel injector of an internal combustion engine configured to supply fuel to a cylinder of the internal combustion engine, comprising:

• a casing, via which the fuel injector can be mounted to the internal combustion engine;
• a valve stem;
• a valve seat;
• a valve body arranged at an axial end of the valve stem configured to interact with the valve seat and acting on the valve stem, the valve body, for opening a fuel flow, is movable in a direction away from the casing or, based on the casing, in a direction towards an outside;
• a guide and seat body comprising:
• a guide portion, wherein the guide portion and seat body guides the valve stem having a first internal diameter corresponding to an external diameter of the valve stem;
• and
• a seat portion having a second internal diameter that is larger than the first internal diameter mounted to the casing, wherein the seat portion of the guide and seat body provides the valve seat for the valve body,
• wherein the guide portion of the guide and seat body are configured to be flowed about by fuel,
• wherein the seat portion of the guide and seat body can be flowed through by the fuel;
• and
• an intermediate portion of the guide and seat body between the first internal diameter of the guide portion and the second internal diameter of the seat portion and having at least one recess, via which the fuel is configured to be conducted from the guide portion in the direction of the seat portion.