[Sca-cooks] Bread allegry

[Suey]

Talking about yeast a friend ate bread in my house recently and his 
stomach became quite upset.  He asked for alka seltzer. I didn't have 
any to his distress. Later trying to clarify the problem he said can eat 
crackers but not bread. Of course he's not the type to go to doctor to 
find out what it is in bread that upsets him. Being a member of our 
group I am afraid of ingredients I could put in food that might upset 
his tummy. Any clues as to what bread has and crackers do not?
Suey