"Herbal medicine damages your liver": we checked the numbers

We put the reassuring numbers and the worrying numbers side by side

Key points in 30 seconds

1. The concern has a basis. In a nationwide study of patients whose livers were damaged by drugs, herbal medicine and herbal products were named as the cause in about 30% of cases.
2. In a study that measured prescribed herbal medicine from medical institutions from the start, 6 out of 1,001 (0.6%) hospitalized patients developed liver injury, and all 6 were found only through blood tests, with no symptoms.
3. An analysis pooling six Korean studies (1,699 people) found a similar 0.71%, and everyone who developed liver injury was also taking conventional medicine.
4. So the conclusion is neither "don't worry, take it" nor "it's dangerous," but "take it while being checked."
5. Herbs you got from a friend, or juices and pills of unknown origin, are outside these numbers.

What we often hear

• "I heard herbal medicine is bad for your liver."
• "When I search for herbal medicine, 'liver' comes up in the related searches."
• "My family talked me out of it, so I haven't been able to decide for months."
• "I'm already on medication. Won't adding herbal medicine strain my liver?"

Many people put off the decision because of this one remark. Today, without defending herbal medicine or scaring you, let's look at it in numbers.

The concern has a basis

There's a nationwide study that looked at the causes in patients hospitalized for drug-related liver damage. In it, herbal medicine and herbal products were named as the cause in about 30% of cases.

Some have pointed out that this category also includes herbs of unknown origin and products from health shops (geongangwon, shops that boil down herbal extracts), not just prescriptions from medical institutions. Even so, a clear fact remains: herbal medicine is medicine too, and medicine can put a strain on the liver.

We don't say "it comes from nature, so it's completely safe."

A study that measured how often it actually happens

Ten Korean medicine hospitals across the country worked together, periodically measuring the liver values of 1,001 hospitalized patients who took herbal medicine every day, throughout the whole time they were taking it. It was a prospective study over about three years. That means it wasn't a look back at collected results; it watched and measured from the start.

Study	Participants	Liver injury
Prospective study at 10 Korean medicine hospitals	1,001 hospitalized patients	6 people, 0.6% (all found only in test values, no symptoms)
Pooled analysis of 6 Korean studies	1,699 people	0.71% (all affected people also taking conventional medicine)

Liver injury meeting international diagnostic criteria occurred in 6 of 1,001 people, and no one developed symptoms such as jaundice.

These numbers need to be read both ways

First, they're far smaller than the picture the worry paints. It means that when 100 people took it, more than 99 had no problem at all.

Second, it still isn't zero. And there's a point you shouldn't miss. In the pooled analysis, everyone who developed liver injury was taking both herbal and conventional medicine.

That doesn't mean taking them together is bad. It means the more medicines go into a body together, the more carefully it needs to be watched.

Being checked means following this order

This is also the order we actually follow.

First, we measure before you take it. Before prescribing, we check your liver and kidney values with a blood test. We need to know at the start whether your liver is normal or already under strain. If you have liver disease or high values, we look at that condition together first.

Second, we check every medication you take, including conventional medicine and supplements. Since liver injury was found in people taking them together, we need to know what's going in alongside it to design the prescription. You should not stop your conventional medicine because you're starting herbal medicine. Adjusting conventional medicine is something to discuss with the hospital that prescribed it.

Third, we measure while you're taking it. If you take it for a long time, we recheck your liver values at set intervals. As the study above shows, liver problems show up in the numbers before they show up as symptoms. That's why we watch with tests, not with how you feel.

Fourth, we tell you in advance the signs that mean you should stop. Unusually severe fatigue, nausea, dark urine, or the whites of your eyes turning yellow. If you have any of these, stop taking it and contact us right away. It's rare, but knowing ahead of time means a faster response. Other things to check before taking it are written up in the post on what to check before taking a tonic.

Medicine of unknown origin is outside these numbers

0.6% is the figure for herbal medicine prescribed and managed by a medical institution after an examination.

Herbs from a friend, juice boiled down at a health shop, or pills of unknown origin aren't included. If you're taking something without anyone having checked what's in it and how much, the problem is less the herbal medicine itself than the missing oversight.

Today's takeaway

Rather than searching more, get checked. Whether you take it after testing or decide not to after testing, either way it will be a decision made by looking at the numbers.

Please bring just two things when you come. A list of the medicines and supplements you take now, and when your liver values were last tested. With those, we'll start by checking together whether your body is in a state to take it.

The judgment differs from person to person depending on your condition and the medicines you take. The principles we follow when prescribing herbal medicine are laid out in our herbal medicine column and treatment guide.

For questions or appointments, message us in English through the messenger at the bottom right of the page, or call +82-53-716-1175.

References

1. Cho JH et al. Prospective study of 1,001 inpatients at 10 Korean medicine hospitals nationwide. Archives of Toxicology, 2017. (Incidence of liver injury 0.60%)
2. Suk KT et al. Prospective survey of 371 cases of drug-induced liver injury in Korea. American Journal of Gastroenterology, 2012.
3. Pooled analysis of 6 Korean studies, 1,699 people, 2015. (Incidence 0.71%; all affected people also taking conventional medicine)

If you'd like to see the original papers, we can show them to you at your visit.