Biology: Neat Facts

• Escherichia coli (E. coli) bacteria is found in the lower intestine. In fact most strains of E. coli are harmless bur some strains are harmful. - Wikipedia
  

• Bacterial infection causes stomach ulcers 80% of the time. (1) One of these is the Helicobacter pylori (H. pylori). Over 50% of the worlds population is infected with this bacteria. But strangely over 80% of these are asymtomatic (2) (show no syptoms). - Wikipedia 1 and 2