10 'Alternative Medicines' That Will Do Some Serious Damage
5. Coffee Enemas

For whatever reason, people just love sticking things up their butts.
Now, if this is something that goes on between two consenting adults then cool, but the claim that sticking your morning cup o' joe where the sun don't shine will somehow cure cancer or "detoxify" the body is taking it too far.
First things first, any time somebody tells you that something will "detoxify" you, and that thing isn't water, alarms bells should go off. Secondly, enemas, particularly when administered by an untrained therapist, carry a real risk of bowel perforation (tearing), internal bleeding, sepsis and severe electrolyte imbalance. It can also interfere with your heartbeat by stimulating the vagus nerve.
What's more, if you're using coffee, you run the risk of burning your colon. This is, as you can imagine, not exactly a day at the zoo.
Enemas should never be performed by anyone other than a medical professional, using sterile saline, either for examination purposes or to treat constipation - not in your bathroom with a litre of Nescafe and a length of hose.