The Cornucopia Institute has launched a campaign against carrageenan, stating that this "natural" food additive is making us sick and needs to be eliminated from the food supply.

Meanwhile WebMd states that "Carrageenan is safe for most people in food amounts. There is a chemically altered form of carrageenan that is available in France to treat peptic ulcers. This form might be UNSAFE because there's some evidence that it might cause cancer."

We suspect the truth is somewhere in the middle, and may indeed have something to do with processing methods. As this article says, Carrageenan is produced in two forms: refined and semi-refined. To produce the refined form, the algae is cooked in an alkaline solution for several hours, then the solid parts of the seaweed are filtered out. The carrageenan is concentrated and removed from the solution, then dried. This method for extracting the substance has been used for hundreds of years, although it is slow and expensive. To produce the semi-refined form, the algae is cooked in an alkaline solution that contains potassium hydroxide. . . . [Meanwhile] It is possible to produce carrageenan at home by boiling Irish moss for about 20 to 30 minutes. When the mixture cools and the moss is removed, much of the carrageenan will have dissolved in the water, leaving a gelled substance.

Here's another take that lets you be the judge by first pointing out that the use of red seaweed to improve a food's characteristics was first employed in China in 600BC and then pointing to some startling, if unsettling, new research (particularly for vegans).