Evaluation of presence of aspirin-related warnings with willow bark.

Background: The dietary supplement willow bark, also known simply as willow, contains salicylates that may present a safety risk to people. Current regulations do not require willow bark to include any cautions on its label.

Objective: To evaluate the absence or presence of label warnings related to salicylates contained in willow bark to ascertain whether a potentially dangerous lack of information exists.

Methods: The label of each willow supplement and willow-containing product was assessed for the presence or absence of 3 warnings: (1) aspirin allergy/sensitivity, (2) use of anticoagulants or "blood thinners," and (3) children with flu-like symptoms or Reye's syndrome. Products from pharmacies and health food stores were targeted and their labels analyzed. A compilation of the identified products was used to conduct a similar evaluation of warnings from their Web sites.

Results: A total of 58 willow bark-containing and 12 single-ingredient willow bark products were assessed. Of the 70 products evaluated, only 8.6% listed a warning. The warning regarding aspirin sensitivity was present on 4.3%, Reye's syndrome was 2.9%, and interactions with anticoagulants/"blood thinners" was 4.3%. One product was labeled as aspirin-free. Percentages were lower on Web sites.

Conclusions: There is a dearth of information regarding potential safety risks on the labels of willow bark and willow bark-containing products. Combination products containing willow bark may pose a greater danger to at-risk patients based on their sheer volume. Counseling of patients who take dietary supplements can improve the situation; however, it may ultimately take improved requirements for dietary supplement labeling to fully address this problem.