What happens if I inject cold water into my veins?

If like they gave you a water iv drip you would die. it would kill you due to changing the water potential. The injected water would rush into your red blood cells and causes the cell membranes to rupture (haemolysis). read more

When you inject water into the veins, first, the plasma will get diluted. This extra liquid will then be absorbed by the cells, especially RBCs in that local area through the process of Osmosis. These cells will then swell up and burst and empty their contents into the blood stream. read more

Probably electrolyte imbalance or congestion depending on the amount of cold water you inject. But if you do inject a reasonable amount (5mL) of sterile water for injection, nothing much will happen save for the cool tingling sensation that you will feel as it goes up your veins. read more

If plain water were injected into a vein it would dilute the contents of the plasma (mainly electrolytes like sodium and chloride, and proteins) in that local area. Through a process called osmosis a portion of the water would fairly rapidly be drawn into nearby cells, in particular the red blood cells. read more