Board Thread:Questions and Answers/@comment-26022697-20150122152450/@comment-4440927-20150122180322

Pen10 wrote: Only thing I can find right now is Albedo saying that a peanut butter seaweed smoothie tastes like cold feet - and is one of Ben's favorites. If Ben were allergic, it definitely would not be a favorite.

OTOH, in "Blukic and Driba Go to Mr. Smoothy's" Way Big claims to be allergic to peanuts - though it's not sure if that applies only to Way Big. His allergy should effects all Ben's aliens. The Omnitrix merges with the users DNA so since Ben is allergic to peanuts, so are all his aliens. Its kinda like how in the episode "Side Effects" when Ben had the cold, all of his aliens were effect by it as well.