Slippery elm bark (Ulmus rubra) has a long history of traditional use in North American herbal medicine, especially by Indigenous peoples and later by European settlers. Its primary constituents include mucilage, which forms a slippery gel when mixed with water. Traditionally, slippery elm has been used internally to soothe sore throats, coughs, and digestive irritation, and externally as a poultice for wounds and minor burns. The use of slippery elm to "support the Structural System"—an umbrella term that may refer to the body's connective tissues, bones, muscles, and skin—is primarily rooted in its historical application to skin and tissue injuries.

However, modern scientific research directly validating slippery elm’s efficacy for supporting the structural system is minimal. Most studies and clinical reports focus on its use for gastrointestinal soothing and for topical relief of minor skin irritations. There is a lack of robust evidence for its effectiveness in strengthening or healing bones, muscles, or connective tissue at a systemic level. The traditional use for external applications does provide some justification for its historical reputation in wound healing and soothing irritated tissues, but this is distinct from systemic structural support as defined by modern medical or nutritional science.

In summary, the support for using slippery elm bark for the structural system is based on traditional topical applications, with little scientific validation for broader or internal structural support.