Those who develop a blood clot in their abdomen may experience swelling and severe pain, as well as nausea and vomiting. In addition, the patient may also experience diarrhea and bloody stools. While these are also symptoms of a stomach virus or food poisoning, it is always important to have these issues checked by a medical professional as a precaution. A blood clot can prevent blood from flowing to the heart, which can lead to a life-threatening situation. Not only that, but researchers are starting to discover that abdominal blood clots may also be a sign of cancer. For example, those who have pancreatic or liver cancer commonly experience abdominal blood clotting.