Liquid Herbal Extract Tussilago farfara Fresh Flowering Tops Contains Less Than 1 ppm of Pyrrolizidine Alkaloids Herbal Dietary SupplementWe prepare our Coltsfoot extract from the fresh flowering tops of Tussilago farfara plants which are Custom Wildcrafted in their natural wild habitat and are never fumigated or irradiated.Through our special extraction process we are able to produce an aromatic, constituent-rich extract that contains less than 1 part-per-million (ppm) of Coltsfoot"s potentially toxic pyrrolizidine alkaloids.