In this Lancet seminar, the authors focus on the understanding and management of peptic ulcer disease over the past 25 years, and cover the following topics:

• Clinical manifestations and diagnosis

• Pathogenesis

• H pylori-positive ulcer

• NSAID-induced ulcer

• Management

• Treatment for H pylori-positive ulcer

• Treatment for NSAID-induced ulcer

• H pylori-negative NSAID-negative ulcer