The tricky thing that other people need to be aware of is that this ingredient is not listed on every product that it might be included in, especially chocolate.
He also found that several different chocolates cause similar yet milder problems, and it wasn't until he contacted companies and demanded that they find out what additional products might have been used but aren't listed (because of loopholes in the laws) that he found this same ingredient used as a thickening agent in chocolate processing.
I'm sharing this information to alert others to warn them about what kind of "natural" substances can also be harmful (carrageenan is made from Irish moss, or seaweed so it appeals to vegetarians and is used in many vegetarian foods ;like Tofu) and how to keep track of what you eat in a journal every single day for every thing you eat and drink.
Write down all of the ingredients or keep wrappers and boxes. Immediately following an outbreak, look over the ingredients in the last 24 hours and compare them to everything else that has been safely consumed to find the ingredients that are upsetting the body. There is so much information available online, you just have to know where to look and find it.
Even though I have never personally experienced any negative effects of carrageenan that I know of, evidence seems to show that carageenan is a harmful food additive. What I learned about carrageenan is enough to convince me to avoid it as much as possible!