Evaluation of presence of aspirin-related warnings with willow bark

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.

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.

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.

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.

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.