Herbal Infusions

Evidence of efficacy for some herbal medicines, but by no means for all those in common use, has increased substantially in the past 20 years. However, most clinical trials of herbal medicine have focused on either standardized extracts of single herbs or standardized formulae reflecting increased sponsorship of such studies by manufacturers in the increasingly important over‐the‐counter market. The individualized approach, in which patients receive tailored prescriptions comprising a mixture of herbs, is emphasized in most forms of practitioner-based herbalism, including European medical herbalism, Chinese herbal medicine and ayurvedic herbal medicine. The world health organization has estimated that 80% of the population in developing countries depends primarily upon herbal medicine for basic health care.2evidence from clinical studies of single herb extracts or standardized formulae cannot be generalized to individualized herbal medicine, and claims by practitioners that the latter has an evidence base requires confirmation. The non‐standardized nature of individually prepared herbal prescriptions and the consequent increased potential for adverse events and negative interactions1 means that safety and effectiveness need to be firmly established before such practices can be endorsed. This systematic review aims to summaries and critically evaluate the evidence from randomized clinical trials for the effectiveness of individualized herbal medicine in any indication. The findings of this review are particularly pertinent because section 12(1) of the UK’s medicines act relating to regulation of unlicensed herbal remedies made up to meet the needs of individual patients is presently under review.

Systematic searches of electronic databases and contacting experts and professional bodies in the field resulted in the location of only three randomized clinical trials of individualized herbal medicine. It should be stressed that professional bodies representing the interests of different practitioner factions from around the world were unable to contribute any more studies than this. In view of the long history and widespread use of medical herbalism, Chinese herbal medicine and ayurvedic herbal medicine in many and diverse indications, this should be a cause for concern. It indicates that individualized herbal medicine has an extremely sparse evidence base and that there is no convincing evidence supporting its use in any indication. Only one of the three studies4 indicated that individualised treatment was superior to placebo and this study is particularly important because it found that individualised treatment was inferior to standardised treatment. This study sets a new benchmark for the tailored approach: not only must herbalists demonstrate that individualised treatment is superior to placebo, they must also show, for reasons of cost and safety, that it is superior to standardised treatment. Claims by herbalists who use the individualised approach that their practice is evidence based are disingenuous; this is because evidence supporting the use of herbs for any indication has come almost entirely from the study of single, standardised herbal extracts, not from studies of individualised herbal medicine using combinations of several or many different herbs prepared from inherently variable raw plant materials. The paucity of data supporting the effectiveness of individualised herbal medicine, and the important safety concerns associated with this particular form of phytomedicine, should be taken into account by policymakers concerned with the regulation of practitioners using this modality.

Implications for future research and clinical practice
Clinical trials do demonstrate that rigorous rcts of individualised herbal medicine are entirely feasible. Care should be taken in the choice of a placebo and success of blinding should be measured. Care should be taken to ensure and demonstrate the success of blinding of patients, herbalists and outcome assessors. There is, however, a problem with the generalisability of results from such studies because of the non‐standardised nature of the treatment. The large number of single herbs from which individualised treatments are prepared, differences between herbalists in prescribing practice, and the lack of information about the actual treatments prescribed all mean that replication of findings will be made difficult. Even if precise prescribing information was reported for each patient, it is difficult to envisage how these data could be productively used when comparing different studies other than for generating hypotheses about particularly effective component herbs. The lack of standardisation and use of multiple herbs in a single prescription also greatly multiply the safety risks. There are additional risks associated with variability in the diagnostics skills of the practitioner, their awareness or lack of awareness of potential interactions, and their ability or inability to identify red flag symptoms indicating serious diseases requiring immediate mainstream medical treatment. Given the risks and lack of supporting evidence, the use of individualised herbal medicine cannot be recommended in any indication.