Most any sweet citrus will do just fine. Can you get Epsom salts or another type of natural salts water that is used to purge the intestines safely? Herbs? Any anti-parasite herb would be fine, just take a safe one morning and night for 30 days or as longa as the fasting continues.
If you do it as the doctor book desribes, you don't use herbs, just fruit juice and 3 days of Epsom salts type purging salts.
It is simple and can be done anywhere in the world that fruit juices are available and where not, dried fruits can be made into a juice and used.