The theory that some forms of arthritis as well as allergic reactions, migraines and other stressful ailments, are caused by harmful bacteria and toxins in the colon, made yucca a natural choice for relief. In fact, veterinarians were using it to successfully treat digestive and arthritic problems in dogs and horses before it came into use by human subjects resulted in evidence that steroid saponin could not only reduce stress and reduce swelling but also improve digestion and decrease the tendency to develop toxic waste in the colon.
In one study, the yucca extract was administered to 149 patients. No therapeutic claims were made. Relief of pain, and swelling and stiffness were reported by 60.7% (The remainder reported no change). There were no ill side effects reported. According to the doctors involved in the testing, the yucca saponin reduces the production of inflammatory toxins in the alimentary canal, relieving the resulting stress problems.