Background: H. pylori eradication therapy is commonly prescribed, but it can lead to life threatening complication.
Case report: We describe a 43-year-old man who developed toxic megacolon because of pseudomembranous colitis following H. pylori therapy. He underwent subtotal colectomy in emergency for peritonitis, and made an
unevetful recovery.
Conclusion: H. pylori eradication with Lansoprazole, Metronidazole and Clarithromycin combination therapy can cause severe pseudomembranous colitis which can be life threatening. It needs early diagnosis and treatment.
This serious complication should be kept in mind before prescribing H. pylori eradication.

Keywords: Clostridium colitis, Helicobacter pylori, pseudomembranous cilitis