If it's a blocked bile duct, yes indeed it helps. It relaxes the duct and lets the stone pass. Means you really need a liver flush.
parasites I don't know. They hang on, and probably aren't really all that flush-able. Sure, some of them, but it doesn't get rid of that many and the block would remain.
Plus doing a Liver Flush with parasites in your liver often makes you feel ill, from Dr. Clark's advice.