It’s not abnormal for the body to bleed occasionally, such as in a nose bleed or with a woman’s menstrual cycle. However, excessive menstrual bleeding, blood in the urine, or frequent, large bruises should be investigated with a hematologist. This also applies to blood that won’t clot (i.e., continuous bleeding).
Abnormal bleeding may have a simple cause, such as a blood thinner medication, or the body have a physiological problem. For example, hemophilia is a genetic disease in which blood doesn’t clot normally.