What are the side effects of herbal teas?

Some herbal teas have strong and even toxic side effects that you should be aware of.

If you are under medication for any reason, see your doctor first before drinking any herbal or regular teas. If, for example, you are taking a blood thinner like warfarin (Coumadin) don’t drink any green tea blend.

Comfrey plant

Comfrey Tea -- For one thing, some people confuse comfrey leaves with those of Foxglove, which is a highly poisonous plant. So get yourself a good plant guide and learn to differentiate these two plants before you do anything else. Comfrey has strong pyrrolizidine alkaloids (PAs) and has been used externally to fix broken bones since the Ancient Greeks. Yet it can also cause permanent liver damage and even cancer if used internally. So it’s better not to drink any comfrey brews at all.

Lobelia plant

Lobelia Tea -- This is another herbal tea you should stay away from since lobelia contains “lobelia,” a yellowish alkaloid that might have a toxic effect similar to nicotine. Although used by Native Americans to cure respiratory problems, the plant also have strong emetic qualities and that’s why it’s also known as “pukeweed,” “gagroot,” and “vomitwort.”

Green Tea -- Although it’s rare, some people experience difficulty of breathing, constriction of their throat muscles, swelling of tongue and lips, and other similar allergic reactions. If you experience any such effects please immediately see your doctor. Heavy use of green tea is also said to be a contributing factor of esophageal cancer. Green tea (as well as many other tea varieties) can also cause heartburn, sleeplessness, irregular heartbeats, headache, etc. if consumed in great quantities in a single day. If you do not feel comfortable, cut down on your tea consumption and see a doctor.

Chamomile plant

Chamomile Tea -- Chamomile has a sedative effect and thus can help if you’re trying to fall asleep in bed.

But if you are driving a vehicle, operating a machine, or doing anything that requires your full attention, then it’s better not to consume chamomile tea at all.

See: What Should You Know About Herbal Teas?