It is unclear whether Helicobacter pylori infection is essential to the dev
elopment of peptic ulcers. In this study, we examined the rates of H. pylor
i-negativity among patients with peptic ulcers. We also attempted to clarif
y the characteristics of H. pylori-negative peptic ulcers to throw light on
the pathogenesis of peptic ulcers. The study included 215 consecutive pati
ents with gastric ulcers (GUs) and 120 consecutive patients with duodenal u
lcers (DUs). After routine endoscopic examination and phenol red dye endosc
opy, forceps biopsies were performed for culture, histology, and the rapid
urease test. A patient was considered H. pylori-negative when the serum ant
i-H. pylori IgG and the three tests on biopsied specimens were all negative
. H. pylori-negative rates were 3.2% in the patients with GUs and 1.7% in t
he patients with DUs. Lack of atrophy of the gastric mucosa was significant
ly more common in the H. pylori-negative patients with GUs. A history of ul
cer disease was less common and antral ulcers were more common in H, pylori
-negative GU patients, but not significantly so. As the urea breath test ha
d not been performed, the possibility of a false-negative result cannot be
completely ruled out, but we believe that the H. pylori-negative rate in ou
r study is more reliable than these rates in previous reports, because we v
isualized H. pylori distribution by phenol red dye endoscopy to avoid false
-negative results in biopsies, and we used both biopsy and serum anti-H. py
lori IgG findings to establish an H. pylori-negative diagnosis. Since H. py
lori-negative peptic ulcers certainly exist, H. pylori infection is thought
not to be essential to the development of peptic ulcers. There were few di
fferences between the characteristics of H. pylori-negative and H. pylori-p
ositive peptic ulcers in our study. A large-scale study is required to clar
ify the characteristics of H. pylori-negative peptic ulcers.