CRD Summary: The review concluded that Ayurvedic and commonly used collateral herbs have shown positive results for the treatment of hyperlipidemia, but that the results should be viewed with caution due to the limitations of the quality scores used. The reliability of the authors' cautious conclusions were uncertain due to lack of reporting of review methods and details of individual studies.

[Approximately half of the included studies assessed garlic. Other herbal products that were assessed included guggal, arjuna and guar gum.]

CRD Commentary: Inclusion criteria were clearly defined in terms of interventions and study designs, but not defined in terms of participants or outcomes. Several relevant sources were searched, but restriction to English-language studies may have resulted in the loss of some relevant data. Methods were used to minimise reviewer errors and bias in the assessment of validity, but it was not clear whether similar steps were taken in study selection and data extraction. Validity was assessed using specified criteria and results of the assessment were reported. However, quality assessment for individual studies were reported only for RCTs, making it difficult for the reader to judge the study validity for themselves. The method used to calculate overall mean safety scores was not provided. Pooling the results in this way seemed inappropriate given the apparent differences between studies. The narrative synthesis adopted for quality and efficacy/effectiveness was appropriate. Results for individual studies were reported without supporting data or levels of statistical significance, which meant that the findings reported in the review could not be verified. Issues of safety and tolerance reported may not be comparable to standards used in conventional medicine. No details were reported for the number or characteristics of study participants, whether controls were placebo or standard allopathic ingredients. The reliability of the authors' cautious conclusions was uncertain due to lack of reporting of review methods and details of individual studies.