Bloody urine
Hematuria (blood in the urine) [5] can be caused by many medical conditions such as kidney disease and cancer. The presence of blood in the urine is always a cause for alarm as this can be indicative of chronic life-threatening disease. If you notice urine in your blood, you should see a doctor to determine the cause.
Sometimes the volume of blood is so little it cannot be seen with the naked eye. Other times, the presence of blood in the urine turns it red or tints the color. The presence of blood in the urine caused by low levels of platelets in the blood often arises from internal bleeding and should be addressed with urgency.
Blood in the stool
Blood often makes the stool appear black and can be difficult to spot. Sometimes this blood is red but this is not as common. Passing out blood with stool is usually caused by internal bleeding in the digestive tracts. The bleeding may be indicative of low blood platelet levels.