Carrageenan, a common and cheap food additive that comes from red seaweed, is used as a thickener and emulsifier in ice cream, yogurt, cottage cheese, soy milk and other processed food products. Based on results of animal studies, it has been tagged by some as an unsafe product that may cause ulcerations and cancers of the gastrointestinal tract. I think the evidence is compelling to avoid carrageenan in any product, and especially if you have irritable bowel disease.
If you are concerned about carrageenan, start by minimizing your consumption of it. Carefully read the labels of the products mentioned above that often contain the additive, and eliminate them from your diet. With a little research you should be able to find healthy products that suit your taste and don't contain carrageenan.
More on the safety of soy milk.