The HemCon Bandage (HemCon Medical Technologies Inc., Portland, OR) is a hemostatic dressing made of chitosan, a complex carbohydrate derived from chitin. The objective of this study was to determine the effectiveness of the HemCon Bandage in a civilian emergency medical services system. The HemCon Bandage was added to the trauma kits of a fire agency and data were collected from June 1, 2005 to August 31, 2006. The dressing was to be used when conventional treatment (pressure and gauze dressings) failed to control external bleeding wounds or for obvious arterial bleeding. Paramedics documented time to cessation of bleeding after HemCon Bandage application as well as wound characteristics and suspected bleeding type. There were 37 uses and complete data were available for 34 cases. Wound location involved the head, neck, or face in 13 subjects and extremities in 18 subjects. There was one case each involving the chest, abdomen, and axilla. The bandage controlled hemorrhage in 27/34 (79%) cases, 25/34 (74%) within 3 min of application. In 25/34 cases, direct pressure had initially failed to control bleeding and the HemCon Bandage was effective in 19/25 (76%). The HemCon Bandage failed to stop bleeding within 10 min in 7 cases. User error was a factor in 6 of the 7 failures. The HemCon Bandage is an effective adjunct for uncontrolled external hemorrhage when traditional measures, such as pressure and gauze dressings, fail.