IBS causes digestive problems like cramping, belly pain, bloating: diarrhea, constipation, or in some cases, both. Medical professionals don't know what causes the condition because it could result from various reasons. Luckily, an herbal diet improves IBS diarrhea constipation and does not require an invasive procedure or surgery. Natural remedies may have fewer side effects compared to prescription medicines. They work to restore the digestive system to normal function.