To the Editor—A recent press release issued by the Department of Health of the Hong Kong SAR Government urged public not to buy or consume an oral health supplement “HemoHIM”.1 This product has been withdrawn from the market in Hong Kong, Taiwan and Singapore. In Hong Kong, from April to September 2021, four women presented to public hospitals because of acute hepatitis (Table).2 All patients had consumed a health supplement named HemoHIM (Atomy; Gongju, South Korea) and liver function improved after cessation of use. No alternative medical causes were identified. A sample of HemoHIM was analysed by high-performance liquid chromatography with diode-array detection and liquid chromatography–tandem mass spectrometry, revealing the presence of methoxsalen, psoralen, and benign herbal markers. Subsequent analysis of additional samples from different sources showed consistent laboratory findings. Methoxsalen (also known as 8-methoxypsoralen, 8-MOP) and psoralen are naturally occurring furocoumarins. They can be found in a number of plant species at various concentrations and are collectively referred to as psoralens. Psoralens have photosensitising property, thus methoxsalen is formulated as drugs used in PUVA (Psoralen and ultraviolet light UVA) treatment for psoriasis and vitiligo.3 Psoralens bind to DNA when exposed to ultraviolet light, inhibiting DNA synthesis and causing a decrease in cell proliferation. Methoxsalen- and psoralen-containing herbs have been reported to cause liver injuries.3 4 The listed herbal ingredients of HemHIM should not contain psoralen or methoxsalen. Further investigations are needed to explain the occurrence of these chemical compounds in the product. Several plant species used in traditional Chinese medicine have been reported to contain psoralens,5 including Fructus Psoraleae (補骨脂, the dried seeds of Psoralea corylifolia), which contains a relatively high concentration of psoralens.2 3 Frontline doctors should be vigilant to patients presenting with symptoms of liver injury after consumption of HemoHIM or other supplements containing Fructus Psoraleae.

CK Chan drafted the letter and all authors contributed to the critical revision of the letter for important intellectual content. All authors approved the final version for publication and take responsibility for its accuracy and integrity.

All authors have disclosed no conflicts of interest.

This letter received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.

1. Hong Kong SAR Government. DH investigates suspected poisoning cases relating to oral product “HemoHIM”. 1 Nov 2021. Available from: https://www.info.gov.hk/gia/general/202111/01/P2021110100785.htm. Accessed 15 Nov 2021.

2. LiverTox: clinical and research information on drug-induced liver injury. Bethesda (MD): National Institute of Diabetes and Digestive and Kidney Diseases; 2012-. Roussel Uclaf Causality Assessment Method (RUCAM) in drug induced liver injury. Updated 4 May 2019. Available from: https://www.ncbi.nlm.nih.gov/books/NBK548272/. Accessed 15 Nov 2021.

3. Cheung WI, Tse ML, Ngan T, et al. Liver injury associated with the use of Fructus Psoraleae (Bol-gol-zhee or Bu-gu-zhi) and its related proprietary medicine. Clin Toxicol (Phila) 2009;47:683-5. Crossref

4. Li A, Gao M, Zhao N, Li P, Zhu J, Li W. Acute liver failure associated with Fructus Psoraleae: a case report and literature review. BMC Complement Altern Med 2019;19:84. Crossref

5. Guo Jia Zhong Yi Yao Guan Li Ju “Zhonghua Ben Cao” Bian Wei Hui. Zhong Hua Ben Cao (中華本草) [in Chinese]. Shanghai: Shanghai Ke Xue Ji Shu Chu Ban She; 1999.