How can some teas cause liver damage?

Toxic. Tea comes from the tea plant (camellia sinensis). Herbal teas come from other plants. Some may contain toxins that can affect the liver cells themselves, the blood vessels in the liver, and/or bile excretion or the bile ducts. Some contain pyrrolizidine compounds which are toxic. Natural does not necessarily mean safe-even if iherb has been used for thousands of years.