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Herbal Medicine Side Effects — From Precautions for Long-term Use to Ingredient Verification and Customized Prescriptions
Blog August 3, 2026

Herbal Medicine Side Effects — From Precautions for Long-term Use to Ingredient Verification and Customized Prescriptions

Dr. Yeonseung Choe
Dr. Yeonseung Choe
Chief Director

When you're in the examination room, there are questions you hear several times a day. "Director, since herbal medicine is made from natural ingredients, does that mean it has absolutely no side effects?" I understand the feeling that natural things seem safe. But herbal medicine is clearly a pharmaceutical product. Just because something is good for you doesn't mean taking more of it or taking it for longer is the right approach.

Is it absolutely safe just because it's a natural ingredient?

Many people think of herbal medicine more as a 'tonic' or 'health supplement' rather than medicine. But herbal preparations are pharmaceuticals made by combining raw herbs collected from animals, plants, and minerals according to traditional Korean medicine principles. Even when formulated with good effects in mind, unexpected reactions can occur depending on a person's constitution and condition.

![A simple pie chart emphasizing the 11% rate of pleural fluid (water) observed among cases of pneumonia after taking traditional Korean medicine. Includes simplified icons of chest X-rays in the background]](/api/files/assets/2026-08/d6ace05b.jpg?sig=d2b8b2cd888c897b31d141de14362c409c7566c2039341fedfa39a733e115141)

Especially problematic moments occur when you do not follow the "prescribed usage and dosage." The habit of long-term intake of ingredients that do not suit your body, or taking medication arbitrarily without professional diagnosis, increases danger. According to research data, even herbal medicines and health foods continue to have reported side effects depending on individual reactions, regardless of where the raw materials came from.

A Dangerous Case Caused by Reckless Long-term Use

A recent case reported from Japan weighs heavily on my heart. A 76-year-old female patient took Kakonto (葛根湯) daily for about 4 months and a half to prevent a cold, and developed severe drug-induced pneumonia. Typically, pneumonia caused by Kakonto tends to occur within 1 month of taking it, but this patient took it without any problems for 4.5 months before symptoms appeared later.

![A table comparing the differences between arbitrary self-medication and customized prescriptions by professionals. (Arbitrary use: High risk, unpredictable / Customized prescription: Safe, efficient tool)]](/api/files/assets/2026-08/8b333921.jpg?sig=9e5bcbb5da7f421c63e6df2bc82403d58929df762bbb9978ffd07caaa489755e)

Ingredients like licorice, commonly found in Ssanghwa-tang or Kalkon-tang, are excellent medicinal materials when used appropriately, but taking them for too long can cause side effects like pneumonia. Previous studies found that among patients who developed pneumonia from traditional Korean medicine, approximately 11% showed pleural effusion (water) on chest CT. It's a regrettable case of harming health while trying to strengthen the body.

Safe usage of herbal medicine from the examination room perspective

The word I always emphasize during consultations is 'context.' Even the same Kalkon-tang can be medicine or poison depending on what stage your body is in right now. Taking it long-term simply because "others said it was good" or "you can easily buy it at a pharmacy" is truly dangerous.

![Checklist for safe herbal medicine use. Arranged with checkboxes for 4 items: check duration of use, check ingredients, stop if abnormal symptoms occur, professional diagnosis]](/api/files/assets/2026-08/b8be1b9f.jpg?sig=e791d9ac38ecaf985ece8404b4557cec9ddbe6171afd3bbc7eac1347040d4a2f)

The core of herbal medicine is 'customized prescription' tailored to one's constitution and symptoms. For example, Zaoren Anshen capsules used for treating insomnia allow for a systematic approach, with research results showing no statistical difference compared to Western medical treatment in terms of clinical efficacy rates under specific conditions, such as a 2g[1] dose. Herbal medicine prescribed under an accurate diagnosis is a safe and efficient tool, but it is unpredictable what reaction may occur from medication taken arbitrarily.

Safe Herbal Medicine Intake Practices to Implement Right Now

Then, how can you use herbal medicine without worrying about side effects? Let me point out a few things.

  • Check the intake period. It is dangerous to continue taking medicine that manages temporary symptoms, like cold medicine, for several months. If you have taken it for a certain period, you must consult a professional to check your condition.

  • Examine the ingredients thoroughly. In particular, it is necessary to check if it contains ingredients that require caution during long-term use, such as licorice, and whether they conflict with your constitution.

  • Stop immediately if abnormal symptoms occur. If you feel mild indigestion, skin rash, unexpected coughing, or pain, do not dismiss it as "just the effect of the medicine" and stop taking it immediately, then visit a Korean medicine clinic.

  • Prioritize professional diagnosis. General herbal preparations sold on the market and customized herbal medicine prescribed by a Korean medicine doctor after a consultation differ from the design principle. The first step is to understand your current metabolic state and constitution.

Medicine taken to become healthy should not instead become a burden. Listening to your body and following a professional's guide is the fastest path to recovery.

If you have taken medicine that did not suit your constitution, or if you have been considering herbal medicine for diet or health management, please feel free to tell us at any time. If you join the Baekrok Gambi-jung tablet program, you can expect safer and more effective results through a detailed analysis of your individual constitution and metabolic state. When you visit next time, let's find the optimal intake method suited to your current state together.

References

[1] Efficacy and safety of Zaoren Anshen capsules in the treatment of insomnia: A meta-analysis of randomized controlled trials. (Medicine, 2020) — https://pubmed.ncbi.nlm.nih.gov/32028417/


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Dr. Yeonseung Choe

Dr. Yeonseung Choe Chief Director

I have met many patients who came after visiting multiple medical institutions and departments for persistent or recurrent conditions. Symptoms normally handled by different specialties—such as abdominal pain, headaches, palpitations, dizziness, and insomnia—may overlap in one person. Sometimes there is no clear improvement despite taking medication for each symptom, and being unwell gradually becomes part of daily life. In these cases, I look beyond individual diagnoses and examine how the symptoms connect and change together. Asking only about the most uncomfortable symptom today does not reveal the full course. I look at when the body first began to change and what happened after illness, surgery, childbirth, or starting and stopping medication. I also review changes in weight, diet, and sleep, then trace which symptoms improved with previous treatment and which remained. Test results, diagnoses, and the course of previous treatment are important for understanding the current condition. Clinical research in modern Korean medicine, physiological and pathological research in modern medicine, and observations recorded in classical Korean medicine texts offer different perspectives on the same body. Rather than fitting a patient into one perspective, I consider what each can and cannot explain and look for clues that connect symptoms and treatment histories that were previously considered separately.

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