Precautions

Blackberry tea contains tannins, plant substances that can have negative effects. Blackberry tea contains hydrolysable tannins such as gallotannins and ellagitannins, which can have toxic effects on the liver in large quantities. Do not drink blackberry tea if you suffer from any type of liver disease without talking to your medical practitioner. Signs of liver damage include yellowing of the skin or whites of the eyes, upper right quadrant abdominal pain, nausea, vomiting and fatigue.