To reduce or prevent a gaseous discharged material, released from a papermaking pulp mill and emitting a malodor when producing a pulp according to the kraft method.

A white liquor or a black liquor or both are brought into contact with undecylenic acid and/or at least one alkyl ester and/or at least one polyoxyalkene ester or at least one salt of the undecylenic acid in the method for treating a gaseous discharged material, containing a volatile sulfur-containing organic compound and generated by the kraft method.