What is the purpose of chenodeoxycholic acid in the treatment of cholelithiasis?

Chenodeoxycholic acid is a bile acid that plays a crucial role in the treatment of cholelithiasis, particularly in the dissolution of cholesterol gallstones. The correct option highlights this specific function: it gradually dissolves gallstones over time. When administered, chenodeoxycholic acid helps to alter the composition of the bile, reducing the cholesterol saturation and eventually leading to the dissolution of cholesterol-rich gallstones.

This process is significant for patients who may not be surgical candidates or prefer a non-invasive treatment strategy for their gallstones. It's important to note that while this treatment can facilitate the slow dissolution of existing stones, it does not provide immediate relief from pain nor does it prevent the formation of new stones entirely. Also, its role is not merely as a digestive supplement but rather a specific intervention targeted at managing gallstone disease.