Human and animal stomachs were considered the only reservoirs of Helic
obacter pylori until it was identified in human dental plaque (DP). H.
pylori is infrequent in populations from developed countries, but is
widespread in those from developing countries. The failure of triple d
rug therapy to clear H, pylori from DP, despite its clearance from gas
tric mucosa, raised the possibility of DP as a permanent reservoir of
H, pylori and a potential source of reinfection of gastric mucosa. Att
empts should be made to eradicate H. pylori both from the gastric muco
sa and from DP to ensure a permanent cure of duodenal ulcer. Unfortuna
tely, all attempts to eradicate H. pylori from DP have failed.