Chewing gum in stomach:
A 1998 paper describes a four-year-old boy being referred with a two-year history of constipation. The boy was found to have "always swallowed his gum after chewing five to seven pieces each day", being given the gum as a reward for good behavior, and the build-up resulted in a solid mass which could not leave the body. A 1½-year-old girl required medical attention when she swallowed her gum and four coins, which got stuck together in her esophagus.
Salt to boiling water:
On Food and Cooking (Revised Edition). cGee, Harold (2004). Page 161, "The Searing Question"
Dr. Pepper Crack:
Not true, couldn’t find a recorded mention of crack in Dr. Pepper
Surge yellow 5:
Pollock, Ellen Joan. "Why Mountain Dew Is Now the Talk of the Teen Circuit." The Wall Street Journal. 14 October 1999
Foods that give nightmares
Honey for infants
Pork and Trichinosis: http://www.latimes.com/world/la-fg-japan-blowfish1-2009apr01-story.html