"Dulce et Decorum est"
The title, in Latin from Horace's Odes, means that it is sweet and decorous (proper/fitting) to die for one's country, is ironic in the context of the theme of the poem.
To say this is satirical in a sense as Owen's expression is mocking the high moralistic standards of soldiers dying at war.
The poem recounts the vile experience of gas suffered by soldiers in action during the Great War. This poem confronts the society of the day with the realities of warfare by stripping away the idealistic representation of heroism and nobility which dominated propaganda at the time. The poem presents a vivid sense of the reality of way and its human impact. There is a curse of the poisoning by mustard gas in the words "as under a green sea, I saw him drowning". Owen depicts how the persona is haunted by his experiences at the western front i.e.
"In all my dreams". These dreams are more like nightmares for Owen and those who suffered with him. Reference to "children" makes like the victory of such a war is like a childhood fantasy.
The theme is to do with the flawed idealism of war, especially as promoted in propaganda to the people at home, as against the horrors of the battlefield which Owen has experienced himself. For Owen there is nothing dignified about the kinds of death that he witnessed at firsthand on the battlefield. He dramatically deflates the romantic heroism of war. WW1 had brought about a new interpretation of human life - a very negative one - and a new kind of artistry was required to capture it. As in many of Owen's poems there is the central theme of soldiers vs. the war. This is because they...