A systematic review and quality assessment of case reports of adverse events for borage (Borago officinalis), coltsfoot (Tussilago farfara) and comfrey (Symphytum officinale).

Symphytum officinale (comfrey), Tussilago farfara (coltsfoot) and Borago officinalis (borage) have long histories of therapeutic use, but their safety has been questioned due to the presence of unsaturated pyrrolizidine alkaloids (PAs). The evidence base underlying these concerns relies in part on case reports. This systematic review assesses these case reports for their reliability to inform this debate. METHOD: Study selection was restricted to case reports describing possible pyrrolizidine alkaloid related harm and ingestion of comfrey, coltsfoot or borage. An extensive search of academic databases was conducted. Papers meeting the criteria were critically appraised. RESULTS: The search resulted in 11 appropriate case reports, none of which involved borage. Nine reports were assessed for causality and indicated some degree of association between the material ingested and the adverse event. Lack of unequivocal identification of the species ingested compromised attribution and was a significant source of uncertainty. Three levels of identity confusions were found; misidentification or substitution at the level of the whole herb; omission of appropriate botanical identification and attribution of a specific PA to either comfrey or coltsfoot when it is a constituent found in other plants of established toxicity. CONCLUSION: These cases are an unreliable body of evidence on which to draw conclusions about the safety of the oral consumption of Symphytum officinale and Tussilago farfara. Toxicological studies based on oral ingestion of phytochemically-complex preparations of these herbs may be the most accurate methodology for assessing clinical risk.

Complementary and alternative medicine in the treatment of chronic liver disease.

Interest in and use of complementary and alternative medicines (CAM) in the treatment of chronic liver diseases has increased in the past decade. However, this has not been supported by a significant increase in sound clinical research evidence for their efficacy. The research literature is growing, providing improved knowledge on population use of CAM, possible mechanisms of action of a large range of complementary and alternative medications, and possible specific indications for these agents in patients with liver disease. Although curative potential for CAM has not been documented consistently in any liver disorder, it is possible to identify anti-inflammatory activity and cytoprotective capacity for a number of agents from different branches of the world of CAM. Evidence grows for potential harm from an increasing number of compounds. Concurrently, clarity is increasing in relation to which specific constituents cause the harm and the mechanisms by which damage is produced.