The goal of the article is to examine if in international public law there is the prohibition of the use of chemical weapons during internal armed conflicts. The first part of the article deals with the previous regulations on the chemical weapons. Secondly, the Chemical Weapons Convention is discussed in relation to the scope of the prohibition. Then, the UN Security Council Resolution 2118 upon the Syrian conflict should be analyzed. Finally, the scope of the prohibition is related to the terms ‘war’ and ‘armed conflict’. The conclusions drawn from the abovementioned analyses depict that there is the strong need for an extension of the existing prohibition; however, no legal act has established it for now.