Laxatives can become addicting and can cause parts of your intestine to die if you use them extensively. Please be careful to use them as directed. As for IBS, it can be with constipation, diarrhea or alternating between the two. IBS D is more publicized but it is about equally devided between the three types according to studies. Zelnorm is only indicated by the FDA for IBS with Constipation and chronic constipation in patients under sixty five so it should only be taken under a doctors direction to ensure it is taken safely. Due to it's mechanism of action though, it may help. Another short term laxative that works well is phosphosoda. It is used as a prep for colonsocopies and can be bought at any grocery store.