I have a new mother on Asacol (mesalamine) for ulcerative colitis. The first metabolite is acetyl-5-aminosalicylate. Aspirin is an acetyl salicylate. The breast milk to plasma ratio for this metabolite is 5.1. The question is: how much of a risk of Reye's syndrome is there for the baby? She will be on this drug long term. She is afraid to try any other drug as an alternative, and would prefer to wean if there is a problem. The baby is a full-term newborn of average weight. The doctor said the compounds were different enough that acetyl-5-aminosalicylate could not cause Reye's syndrome. I thought any salicylate was a risk factor. I have tried to reach CDC without luck so far. Of course, I would prefer her to breastfeed, but she and I need to know whether there is an actual risk of severe CNS damage should the baby be exposed to the type of virus which works with salicylates to cause Reye's syndrome. The mother has had chicken pox previously, so has antibodies to share with her baby, if that makes a difference. Arly Helm (who hopes she got the drug names right, as her notes are at work) [log in to unmask] (Arly Helm, MS, CLE, IBCLC)