I flush whenever I have a feeling of heaviness or pain in my liver/GB. It tends to be every 2-3 months. A flush can cause some toxic symptoms for a while as the contents of the flush passes through your digestive tract so it may be a day or two before you feel better. But once the liver/GB is cleaned out it gives your body a new lease on life.
If you have a acute pain after a flush you can take 2 TBSP magnesium citrate in very warm water and it should relieve the pain very quickly. A tsp of epsom in very warm water will work as well.