Nonsteroidal anti-inflammatory drugs (NSAIDs) relieve rheumatic pain and are in extensive use. Symptomatic complications of NSAIDs requiring the discontinuation of their use occur in 2 to 10 percent of patients with rheumatic diseases in sharp contrast to the common asymptomatic problems of gastroduodenal erosions, ulcerations, and bleeding, with resulting anemia in more than 40 percent of these patients. Opinions concerning the clinical significance of these complications are not uniform. The natural history of the effects of NSAIDs on the gastroduodenal mucosa reveals a sequence of initial subepithelial hemorrhage over a 24-hour period followed by gastroduodenal erosions and ulcerations in the next two weeks. From one week to three months, gastroduodenal erosions and ulcerations disappear in about half of the patients as an adaptation to continuing NSAID ingestion occurs. Hemorrhage may occur at any time in most patients and in a small minority (1 percent) it is massive. Non-aspirin NSAIDs (NANSAIDs) exhibit significantly fewer complications than do aspirin. These complications, however, demand considerable clinical attention and are ordered in a constant hierarchy, suggesting variable risks of complications among agents. NSAIDs are a blessing for those who have chronic pain, but that blessing does not prevent significant asymptomatic complications in the same patients. Prophylaxis for high-risk groups, such as women over the age of 65 years, should be subjected to study.