To prevent headaches, cleanse your bowel before you start liver cleanse.
On the morning of the liver cleanse, take and enema, and make sure that your colon is clean. Repeat enema 2 - 3 times. That will, in most people, prevent headache.
Headache usually means you have toxic bowel.
Also, take less epsom salt, 2 tbsp.
In the morning, next day, do enema agin, that will insure that you really flush everything out from your colon.
Also, avoid industrially processed foods at least 5 days prior the flush, most headache is caused by industrial food additives