The Shining - The River of Blood

The river of blood appears in The Shining (1980) as an unsettling and nerve wrecking scene, 6 year old Danny experiences a flood of blood burst from a doorway in the hotel while standing in shock. As mentioned previously, Danny is experiencing symptoms that may point to PTSD and MDD. Whether or not the river of blood was real, it can be speculated that it is a hallucination that Danny is experiencing. There are many interpretations behind what this experience means to Danny and the film as a whole. The director crafts this scene to invoke a feeling of dread, for something oncoming to Danny and his family. This leads to the theory that the river is symbolic of inevitable death that is coming for everyone, whether it will be slow or fast. The director creates this scene with growing tension, as the river slowly gets closer to Danny. This can symbolize the oncoming danger is slowly coming for his family. 
In addition, we also theorized that the scene captures how the rush of blood engulfs the hall in a way that invokes the fear of drowning. Perhaps it represents death drowning us out, with a pool of blood growing bigger as death does its part on our bodies. The river of blood can be seen as death slowly taking us away, not always with us physically bleeding out, but generally as the onset of death. This can be seen in Danny’s expression, as he is seen standing in shock and fear. This can be either a nightmare or hallucination that Danny is experiencing, resulting from the stressors present in the child’s life. 
However, WikiKnights has theorized that the river of blood points to Danny being afflicted by Wendigo’s psychosis. Danny shows signs of trauma and intense fear in certain scenes of the film, other than the river of blood. He is seen entering Room 237, regardless of being warned to stay out. This results in him experiencing something that hurts him and he is afflicted with trauma. Wendigo’s psychosis is culturally taboo within a native American tribe and afflicted by those who think about cannibalism. We can theorize that the river of blood represents lost native American lives, whether it was cannibalism or murdered by colonialism. It is also debatable whether spirits or malevolent souls of those dead are afflicting Danny and his family, however, scenes such as the river of blood and Room 237 point to Danny experiencing the effects of Wendigo’s psychosis.