Final answer:
Non-specific smooth muscle relaxants decrease gastrointestinal motility to ease IBS symptoms. Soluble fiber supplements and vegetable gum fibers like guar gum may provide relief by modifying gut inflammation and function.
Step-by-step explanation:
A non-specific smooth muscle relaxant used in the treatment of irritable bowel syndrome (IBS) can relieve symptoms such as abdominal discomfort, diarrhea, and constipation by decreasing the motility of smooth muscle in the gastrointestinal tract. While the role of serotonin is significant in the gastrointestinal function, the exact relaxing agent for IBS isn't provided in the question. However, managing IBS may also involve dietary modifications, and the use of soluble fiber supplements can be beneficial. These supplements, which include inulin and oligosaccharides, may alleviate IBS symptoms due to the anti-inflammatory effects of short-chain fatty acids produced by them. Furthermore, vegetable gum fibers like guar gum and gum arabic, have demonstrated efficacy in preliminary clinical trials for IBS treatment.