European herbalists have been using butterbur for decades and scientific studies have demonstrated that petasins, the active constituents in butterbur, can support healthy blood flow to the brain and promote normal neurological function.* In this way, butterbur may help to maintain head comfort in healthy individuals.* NOW? Butterbur is also free of undesirable pyrrolizidine alkaloids (PAs), so it can be used regularly. Natural color variation may occur in this product.