Coffee enemas can cause numerous side effects, including infections, sepsis (including campylobacter sepsis), severe electrolyte imbalance, colitis, proctocolitis, salmonella, brain abscess, and heart failure. If the coffee is inserted too quickly or is too hot, it could cause internal burning or rectal perforation.
The use of coffee enemas has led to several deaths as a result of severe electrolyte imbalance, hyponatremia, dehydration, pleural and pericardial effusions. The U.S. Food and Drug Administration (FDA) has ruled that study participants must be warned of the risk of death from coffee enemas in studies that use them.