By skyforbes 
They cause almost a quarter of all liver damage. Herbs like borage, comfrey, groomwell, and coltsfoot have “pyrrolizidine alkaloids” that can gum up the tiny blood vessels inside your liver, either over time or all at once (if you take a lot). Other herbs like Atractylis gummifera, celandine, chaparral, germander, and pennyroyal oil (used in tea) can also cause liver problems. Check with your doctor before starting any supplement. Stop taking supplements right away and contact your doctor if you have side effects including extreme tiredness, swelling joints, abdominal discomfort, or back pain.