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Summary
Bleeding is the loss of blood. It can be external, or outside the body, like when you get a cut or wound. It can also be internal, or inside the body, like when you have an injury to an internal organ. Some bleeding, such as gastrointestinal bleeding, coughing up blood, or vaginal bleeding, can be a symptom of a disease.
Normally, when you are injured and start bleeding, a blood clot forms to stop the bleeding quickly. Afterwards, the clot dissolves naturally. To be able to make a clot, your blood needs blood proteins called clotting factors and a type of blood cell called platelets. Some people have a problem with clotting, due to another medical condition or an inherited disease. There are two types of problems:
- Your blood may not form clots normally, known as a bleeding disorder. This happens when your body does not make enough platelets or clotting factors, or they don't work the way they should.
- Your blood may make too many clots, or the clots may not dissolve properly
Sometimes bleeding can cause other problems. A bruise is bleeding under the skin. Some strokes are caused by bleeding in the brain. Severe bleeding may require first aid or a trip to the emergency room.
Diagnosis and Tests
- Blood Test: Factor VIII Activity (Nemours Foundation) Also in Spanish
- Blood Test: Prothrombin Time (PT) (Nemours Foundation) Also in Spanish
- Partial Thromboplastin Time (PTT) Test (National Library of Medicine) Also in Spanish
Treatments and Therapies
- Severe Bleeding: First Aid (Mayo Foundation for Medical Education and Research) Also in Spanish
- What Do I Need in My First Aid Kit? (American Academy of Family Physicians) Also in Spanish
Specifics
- About Vitamin K Deficiency Bleeding (Centers for Disease Control and Prevention) Also in Spanish
- Anemia Due to Excessive Bleeding (Merck & Co., Inc.) Also in Spanish
- Blood in Urine (National Library of Medicine) Also in Spanish
- Gastrointestinal Bleeding: MedlinePlus Health Topic (National Library of Medicine) Also in Spanish
- Intracranial Hematoma (Mayo Foundation for Medical Education and Research) Also in Spanish
- Nosebleeds (American Academy of Family Physicians) Also in Spanish
- Subconjunctival Hemorrhage (Broken Blood Vessel in Eye) (Mayo Foundation for Medical Education and Research)
- Vaginal Bleeding: MedlinePlus Health Topic (National Library of Medicine) Also in Spanish
Genetics
- Warfarin sensitivity: MedlinePlus Genetics (National Library of Medicine)
Videos and Tutorials
- Blood clotting (Medical Encyclopedia) Also in Spanish
Clinical Trials
- ClinicalTrials.gov: Hematoma (National Institutes of Health)
- ClinicalTrials.gov: Hemorrhage (National Institutes of Health)
Journal Articles References and abstracts from MEDLINE/PubMed (National Library of Medicine)
- Article: Bleeding and Thrombotic Events in Hemodialysis Patients with Atrial Fibrillation on...
- Article: Autoantibodies immuno-mechanically modulate platelet contractile force and bleeding risk.
- Article: Development of a simplified model and nomogram for the prediction of...
- Bleeding -- see more articles
Reference Desk
- Hematology Glossary (American Society of Hematology)
Find an Expert
- Find a Hematologist (American Society of Hematology)
- National Heart, Lung, and Blood Institute
Children
- Blood in the Urine (Hematuria) (For Parents) (Nemours Foundation) Also in Spanish
- Dealing with Cuts (For Parents) (Nemours Foundation) Also in Spanish
- Embolization (For Parents) (Nemours Foundation) Also in Spanish
- Nosebleeds (Nemours Foundation) Also in Spanish
- Nosebleeds (For Parents) (Nemours Foundation) Also in Spanish
- What's a Scab? (Nemours Foundation) Also in Spanish
Teenagers
- Nosebleeds (Nemours Foundation) Also in Spanish
Patient Handouts
- Bleeding (Medical Encyclopedia) Also in Spanish
- Bleeding gums (Medical Encyclopedia) Also in Spanish
- Bleeding into the skin (Medical Encyclopedia) Also in Spanish
- Intraventricular hemorrhage of the newborn (Medical Encyclopedia) Also in Spanish
- Subarachnoid hemorrhage (Medical Encyclopedia) Also in Spanish
The information on this site should not be used as a substitute for professional medical care or advice. Contact a health care provider if you have questions about your health.