Why would you want to take the gel as opposed to the liquid? I use George's Roadrunner Aloe Vera juice and have had no problems.
Carrageenan, a type of seaweed used as a thickening agent, is not recommended for IBDers regardless of whether or not it's considered carcinogenic because it is used to induce colitis in laboratory rats. You can read more about
it here:
http://www.annieappleseedproject.org/carandcolcan.html
And Dr. Ronald Hoffman had this to say:
Carrageenan is classified as an algal polysaccharide produced from seaweed. It's safety for human consumption was questioned after it was discovered that it could injure the intestines of laboratory rats in 1982. Animal studies have shown that sulfated polysaccharides, such as carrageenan, increase hydrogen sulfide production. Hydrogen sulfide production inhibits the metabolism of butyric acid and other short chain fatty acids, which in turn starve colonocytes, and induce lesions similar to ulcerative colitis. Avoiding sulfate consumption from preservatives such as sulfites and sulfur dioxide may be beneficial for IBD patients.
Carrageenan is ubiquitous in our food supply, and can be found in all sorts of alternative milk products such as soy milk, rice milk, grain milks, rice dream, soy dream, and tofu products, veggie burgers, cereals, baked goods, tooth pastes, supplements, and soups. The worst offender is the herb Irish moss because it is pure carrageenan.