Do herbal medicines negatively affect liver tests? A systematic review of Korean clinical studies on safety

IntroductionThe use of herbal medicine (HM) is common, but there are concerns about the potential adverse effects of HMs on liver function. This study aimed to assess the effect of Korean HM in studies where liver function was measured. Additionally, the incidence of liver injury following the use of Korean HM was investigated.MethodsThis study involved systematic searches of eleven Korean Medical databases and two journals related to HM research through December 2013. All articles that reported clinical trials in which any type of human patient was treated with any type of HM were included. Three independent authors reviewed the literature based on specific inclusion and exclusion criteria.Results43 studies met the inclusion criteria. 23 studies were performed prospectively. In terms of the incidence rate of liver injury, none of the prospective studies reported liver injury rate incidences. One study reported 3 cases of liver injury and another study reported 5 cases of liver injury in patients treated with HM in retrospective studies. Additionally, 4 case reports were on liver injury patients who were treated with HM. All retrospective studies were case-series studies. Among the prospective studies, 6 studies were randomized controlled trials, and 2 studies were case-control studies.ConclusionsThere was insufficient evidence suggesting that the use of HMs affected patients' liver injury incidence. The risk of liver injury caused by HMs is thought to be small, but it could not be determined whether this was the case for individual HMs due to both the heterogeneity of the patients and the range of HMs prescribed.This article belongs to the Special Issue: Ensuring and Improving Patients' Safety in Integrative Health Care.