The invention relates to an arrangement for reducing fuel material slip to the atmosphere in a an internal combustion piston engine with at least two cylinders (14) and at least one turbo charger unit (28), the arrangement comprising an exhaust gas system (24) arranged to connect a combustion chamber of each cylinder of the engine controllably by means of an exhaust valve or valves (23) to the atmosphere via a turbine section (28.2) of the at least one turbo charger unit, fuel processing unit (34) for oxidation of fuel material in the exhaust gas of the engine.; In the arrangement there is a flow path (32) provided opening into the exhaust gas system (24) in the vicinity of the exhaust valve of each cylinder at a side opposite to the combustion chamber, and in which the fuel processing unit (34) is arranged into the flow path (32) to receive and process fuel material in the exhaust gas. Invention relates also to method of reducing fuel material slip to the atmosphere and a cylinder head (50) for an internal combustion piston engine.