I have worked out that my son's bad behaviour is all due to added MSG. He is OK on cheese and other natural MSG products - but give him a KFC chicken nugget packet and their chicken salt chips with the so called "secret herbs and spices" and you can see the reaction within 30 to 60 minutes. I'm not surprised as I get very similar reactions with MSG although my reaction is different to my son's behavioural reactions. I have Irritable Bowel and my reaction to MSG is to have a bad IBS attack. Sometimes I get an almost "high on drugs" feeling where my skin starts to crawl. - reader, email