To Finch:
We use flax in addition. As far as I know, it does not have the same effect as CLO. Do you think your son was allergic b/c of the fish element? I ask b/c the one I use is lemon essence infused and is by Carlson. I wonder if the allergy was to fish or to something else in the oil?
Anyway, there are tons of links about the subject. Here's one comparing flax and CLO: hope it works! I also cut and pasted part of the article
http://www.mercola.com/2003/jan/22/cod_liver_oil.htm
DHA is primarily obtained from fish sources, not plant sources like flax seed. Very little of the omega-3 fat ALA in flax seed oil is converted to DHA. So don't try to achieve the same results by using flax seed oil instead of fish or cod liver oil. While I am a major fan of freshly ground organic flax seeds, you need a high-quality animal source of omega-3 fat to receive its maximum benefits.
I am convinced that it is a lack of omega-3 fats that predisposes children to developing the brain injury from vaccines that results in autism, pervasive developmental delay and ADHD. Always remember omega-3 fats are essential to your, and your children's, health. The best source for omega-3 is fish oil and cod liver oil.
When choosing your fish oil or cod liver oil, it is important to remember that not all brands are the same. In my research -- and in my clinical experience with my patients -- I have found that 1) the liquid form is superior to capsules; 2) that certain brands definitely seem inferior to others; 3) that the Carlson's brand of fish oil/cod liver oil is of exceptional quality and purity. It is likely not the only brand in the world of such high quality, but up to this point it is the only one of such quality that I can recommend, so I now offer Carlson's fish oil and cod liver on Mercola.com; you can also check your local health food store to see if they carry it.