I have used supplement pills that contain herbs and mostly fiber. I'd warn to be careful with those! Even when drinking the recommended amount of water, the extra fiber caused some problems
I also can't see how the 'only drink grapefruit juice for a week' type thing is a good idea. Seems to go against everything I ever learned about how we lose weight and build muscle, yet I see so many people trying that kind of thing.
My family does a only fruits and vegetables cleanse every few months. No fancy pills, nothing crazy. There are enough ways to get protein with only fruits and vegetables. We make guacamole. Instead of chips we use cucumber slices. We make soups with garbanzo (chichi) beans. We cook lots of sweet potatoes. We're not super strict about it but we completely cut out fried stuff, meats, dairy and anything processed for 2 weeks and it makes a huge difference!