Background: In recent times, herbals or phytomedicines have become very popular due to their global
acceptance as a complementary and alternative remedy. While modern drugs are commercially available only after
laboratory validations, clinical trials, as well as approval from drug regulatory authorities, majority of the marketed
herbal products lack such scientific evidence of efficacy and safety. This results in herb or herb-drug interaction
induced unfavorable clinical outcomes without crucial documentation on their temporal relations and concomitant
Methods: An online literature search for peer-reviewed articles was conducted on the PubMed, Europe PMC, Medline
and Google Scholar portals, using the phrases: complementary & alternative medicine, traditional Chinese medicine,
herb-drug interaction, mechanisms of herb-drug interaction, herb-induced toxicity, herbal hepatotoxicity and
causality, traditional medicine, viral hepatitis, etc.
Results: The retrieved data showed that globally, patients are attracted to herbal remedies with the misconception
that these are completely safe and therefore, use them simultaneously with prescription drugs. Notably, there exists a
potential risk of herb-drug interactions leading to some adverse side effects, including hepatotoxicity. The toxicological
effect of a drug or herb is due to the inhibition of drug metabolizing enzymes (e.g., cytochrome P450), including
interactions with certain prescription drugs through various mechanisms. Several cases of hepatotoxicity due to
use of herbals in viral hepatitis-related liver diseases have been recently reported. However, limited experimental
data and clinical evidence on herbal pharmacokinetics hamper the evaluation and reporting of adverse reactions and
the underlying mechanisms.
Conclusion: Herb-drug interaction related morbidity is thus an emerging serious public health issue with broad implications
for clinicians, pharmaceutical industries and health authorities. Nonetheless, despite increasing recognition
of herb-drug interaction, a standard system for interaction prediction and evaluation is still nonexistent. This review
article discusses the herb-drug interactions related hepatotoxicity and underlying mechanisms, including drug metabolizing
enzymes and their regulation.