Herb Pharm, Khella, Mature Seed, 1 fl oz (29.6 ml)Respiratory System Herbal Supplement Khella Liquid Extract We prepare our Khella extract from the seed of Ammi visnaga plants which are Certified Organically Grown or Sustainably Wildcrafted in their natural habitat. To assure optimal extraction of Khella's bioactive compounds, the seed is harvested only when fully mature, is cleaned of superfluous plant materials and is then thoroughly extracted.