The 27-line poem, written loosely in iambic pentameter, first describes war-weary soldiers marching "through sludge," "blood-shod," and "drunk with fatigue." Then mustard gas shells fall and the soldiers scramble to get their gas masks on. One man is too slow, and the narrator sees him "guttering, choking, drowning."
In the final verse, Owen writes that if readers could see the body--the "eyes writhing," the "face hanging," the "vile, incurable sores on innocent tongues"--then people would cease sending young men to war with visions of glory in their head. Owen quotes the Roman poet Horace: "Dulce et decorum est/ Pro patria mori" ("It is sweet and proper to die for one's country") and calls these words "the old lie."
The poem is made all the more poignant because Owen died in battle four days before the armistice was signed that ended World War I.