debate, dr. carson denied having links to the nutritional company mannatech. take a look. >> i didn't have an involvement with them. that is total propaganda and this is what happens in our society. total propaganda. i did a couple speeches for them. i do speeches for other people. they were paid speeches. it is absolutely absurd to say that i had an kind of relationship with them. do i take the product? yes. i think it's a good product. >> well, as we reported before, dr. carson is claiming he has no ties to mannatech don't stand up to scrutiny. tonight dr. drew griffin has more information. >> it's a good product. >> reporter: this is the product at the center of the political controversy. a dietariry supplement sold by a company called mannatech made up of tree bark, aloe gum and product supposedly to support better health. in 2013 mannatech reported sales