kelp is a plant(herb) that comes from the ocean and you can buy it as a capsule or as a liquid. make sure you buy quality kelp though that is from a trusted company or it could have pollution. i think it comes in powder form too, but i don't take it that way as i would have to put it into juice, and i can't drink juice. Nature's Sunshine or Pure Herbs is a good brand, and I am sure there are others. i get it from my iridologist, but i am sure you can get a good kind at the health food store or from a chiro. leslie