The bark of different varieties of willow has had a long history of medical use as a means to reduce fever and as a painkiller. Willow bark is also used in weight loss and sports performance food supplements.
The labelling of these products usually does not mention any restrictions to the length of use. The recommended doses for foods differ, sometimes exceeding doses recommended for pharmaceuticals.
A systematic literature review on adverse effects potentially resulting from oral exposure to white willow Salix alba was performed. The aim of the study was to assess the risk for humans when consuming white willow bark in food.
The preliminary results show that despite the long history of use only very limited data on toxicity of white willow bark are available. However, anaphylactic reactions in people with a history of allergy to salicylates may occur. Some other adverse effects of salicylates are considered to be of low relevance for the long-time consumption of white willow bark, mainly due to relatively low concentrations of salicin and the presence of compounds with gastroprotective action.
However, it seems that the content of heavy metals, mainly cadmium, should be further addressed in risk assessment of white willow bark in food. Keywords: Salix alba; White willow; bark; cortex; food; food supplements; risk assessment.