Coffee-colored stools may not be shaped because of peptic ulcers, consuming foods that cause the stools to turn black, and other reasons. 1. Peptic ulcers: the most common are gastric ulcers, duodenal ulcers, etc., which can lead to irregular stools, frequent diarrhea, etc. If peptic ulcers are accompanied by bleeding, the blood is mixed into the feces, and the iron is oxidized, which can lead to the feces not being shaped to turn into coffee color. 2. Consumption of food that causes the stool to turn black: if you consume pig blood, duck blood, spinach, activated charcoal powder, ferrous succinate and other food that can make the stool turn black, it will cause the stool to be coffee-colored and unshapely. Other cases such as gastric cancer with bleeding can also be seen in coffee-colored and unshaped stools. It is recommended to go to the hospital for examination to clarify the situation and give symptomatic treatment.