Ulcers of the duodenum commonly occur because of infection by the bacteria "Helicobacter pylori". Common causes include "Helicobacter pylori" and NSAIDs. Common causes include infection with "Helicobacter pylori" and use of nonsteroidal anti-inflammatory drugs (NSAIDs). Some common examples of misdiagnosis include infectious diseases, coeliac disease, "Helicobacter pylori", parasites (non-protozoal). Common causes include the bacteria "Helicobacter pylori" and non-steroidal anti-inflammatory drugs (NSAIDs). It can also inhibit the growth of "Helicobacter pylori". About 75% of individuals infected with "H. pylori" develop gastritis. Chronic gastritis (inflammation) caused by "H. pylori" is often long-standing if not treated. Barry Marshall treated his own gastritis, which developed following intentional ingestion of "H. pylori" culture. Several regimens are used to treat "H. pylori" infection. Achieving optimal eradication of "H. pylori" has proven difficult. Some believed that mastic gum, a tree resin extract, actively eliminates the "H. pylori" bacteria. Some types of lymphoma can be cured by eliminating "H. pylori". Bovine lactoferrin has more activity against "H. pylori" than human lactoferrin. Its usefulness in people infected by "H. pylori" is limited.