What kind of ulcers are not caused by bacteria?

Ulcers that are not caused by bacteria include stress ulcers, which are often linked to severe physical stress or trauma, and chemical ulcers, which can result from exposure to harsh substances like certain medications or corrosive chemicals. Additionally, radiation ulcers may develop following radiation therapy for cancer. These types of ulcers differ from peptic ulcers, which are primarily associated with Helicobacter pylori infection.