There is no official count of dog deaths available for the race's early years and this count relies only on a reported number of deaths. Causes of death during the last ten years have included strangulation in towlines, internal hemorrhaging after being gouged by a sled, liver injury, heart failure, and pneumonia. In 1985 a musher kicked his dog to death. In 1996 Rick Swenson's dog died while he mushed his team through waist-deep water and ice. Many Iditarod dogs have gastric ulcers and some have died from this condition.
Ulcers predispose the dogs to vomiting.
Normally, the trachea closes the airway so that foreign material does not enter the lungs. But because these dogs run at such high speeds for such a long period of time, they cannot stop gasping for air despite the vomiting. Consequently, dogs inhale the vomit into their lungs which causes suffocation and death. These drugs reduce swelling, inflammation, relieve pain and fever, which allows the dogs to run farther and faster. Unfortunately, some dogs pay with their lives for the use of these drugs.