Duodenal substance, typically sourced from bovine or porcine duodenum, has been used in some traditional or "organotherapy" practices to support digestive health, including in contexts where the gall bladder is considered "sluggish" or has been removed. The rationale behind its use is based on the belief, prominent in early naturopathic and alternative medicine circles, that consuming animal organ extracts can support or "nourish" the corresponding human organ or system. In the case of gall bladder issues, proponents suggest that duodenal substance may help support digestion and bile flow, as the duodenum plays a key role in receiving bile and pancreatic enzymes for fat digestion.

However, there is little to no scientific evidence supporting the efficacy of duodenal substance for this purpose. Modern clinical research does not validate the concept of "like supports like" or the idea that oral consumption of animal duodenal tissue influences human gall bladder function or compensates for its absence. The evidence for its use is largely anecdotal or rooted in historical practices, rather than rigorous scientific validation. Therefore, while its use is traditional, the strength of evidence is very weak (rated 1), and it is not endorsed by mainstream medicine for gall bladder support or treatment.