Recently, we see that green tea is being heavily promoted for its antioxidants and supposed benefits for the heart and metabolism. But the truth is that it isn’t as safe for everyone as it seems. There are certain green tea contraindications that you should be clear about before turning it into your daily drink.

This tea comes from the leaves of Camellia sinensis, which, unlike others, are steamed or cooked to preserve their properties. What’s interesting is that it contains polyphenols, especially catechins, which have a powerful antioxidant action. It also contains vitamin K, which supports blood clotting. Many people choose it because it has less caffeine than coffee, so it helps with concentration without the jitters.

Now, this is where the important part comes in. The MDS Health Manual has reported cases of liver damage from green tea consumption, especially when it’s taken on an empty stomach. When you ingest tea on an empty stomach, catechin levels rise, and that can overload the liver. It’s not the most common thing, but it’s a real risk.

Another key point about green tea contraindications has to do with medications. If you take warfarin or other anticoagulants, be careful. The vitamin K in tea can reduce the effect of these drugs. Also, EGCG (one of the main antioxidants) interferes with the absorption of these medications at the intestinal level. There is also a rebound effect if you stop drinking tea suddenly: lithium levels may increase and cause problems.

People with anemia or nutrient deficiencies should also think twice, because green tea interferes with the absorption of iron and folic acid. On the other hand, although it has less caffeine than coffee, if you take too much it can cause insomnia, anxiety, palpitations, or tremors—especially if you’re sensitive. That’s why pregnant women, breastfeeding women, children and teenagers, and those with heart problems should avoid it.

If you want to drink green tea with less risk, there are a few things you can do. First, never take it on an empty stomach, especially if it’s a strong infusion or an extract. Second, don’t overdo the dose—although it has good polyphenols, excess is dangerous. Third, if you’re taking medications like warfarin, talk to a doctor first. Fourth, it’s safer to drink green tea than to take supplements or concentrated extracts, because the latter have catechins in very high levels. And finally, if after taking it you feel discomfort, stop and consult a professional.

Green tea contraindications don’t mean you can’t take it; it just means you need to be aware of the risks based on your personal situation. The key is to inform yourself properly and consume it responsibly.