Internal Bleeding: A Comprehensive Guide to Recognizing Symptoms and Seeking Care
Updated: 3 days ago
Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: October 17, 2026
Quick Answer
Internal bleeding (hemorrhage) is blood collecting inside the body after blood vessels burst or break, most commonly from trauma such as a vehicle accident. Warning signs include lightheadedness, shortness of breath, weakness and a fast heart rate. Losing more than 30% of blood can cause severe symptoms and shock. Hospital treatment can include surgery, IV fluids and transfusions. [1]
What the research says
Tranexamic acid reduces deaths in bleeding trauma patients. The CRASH-2 randomized trial enrolled 20,211 adult trauma patients with, or at risk of, significant bleeding and gave them tranexamic acid or placebo within 8 hours of injury. All-cause mortality was lower with tranexamic acid (14.5% vs 16.0%; relative risk 0.91, 95% CI 0.85 to 0.97), as was death due to bleeding (4.9% vs 5.7%; relative risk 0.85, 95% CI 0.76 to 0.96). (Shakur et al., Lancet, 2010)
A balanced blood-product ratio helps control bleeding. In the PROPPR trial of 680 severely injured patients predicted to need massive transfusion, giving plasma, platelets and red blood cells in a 1:1:1 ratio versus 1:1:2 did not significantly change mortality at 24 hours (12.7% vs 17.0%) or 30 days (22.4% vs 26.1%). However, deaths from exsanguination within 24 hours were lower (9.2% vs 14.6%) and more patients achieved hemostasis (86% vs 78%). (Holcomb et al., JAMA, 2015)
What is internal bleeding?
Internal bleeding (hemorrhage) happens when your blood vessels burst or break and blood collects inside your body. There are many causes and they vary in severity. It can happen almost anywhere inside the body, and it can be sudden and rapid or slowly build up. [1]
No type of internal bleeding is normal, except regular menstrual bleeding, and it can very quickly become life-threatening. Get medical help as soon as possible if you think you or someone near you has internal bleeding. [1]
Visible and not visible internal bleeding
Visible internal bleeding
The most common type of visible internal bleeding is a bruise, which is skin discoloration from damaged, leaking blood vessels under the skin. Some internal bleeding becomes visible when blood leaks from a body opening or shows up in waste products: [1]
Bowel damage: bleeding from the anus or blood in the stool.
Head or brain injury: bleeding from the ears or nose.
Damage to the esophagus, stomach or duodenum: bloody vomit.
Lung damage: coughing up blood.
Urinary tract damage: blood in the urine (hematuria).
Damage to the uterus, cervix or vagina: abnormal vaginal bleeding.
Damage to the prostate, testicles or seminal tract: blood in the semen.
Not visible internal bleeding
You can have bleeding inside your body that you can't see. You'll likely have symptoms such as pain, weakness or lightheadedness, and they vary with the area of bleeding, the severity of the damage and the amount of blood lost. [1]
Symptoms and severity levels
How internal bleeding feels depends a lot on where it is and how severe it is. Healthcare providers describe severity by the share of total blood volume lost. [1]
Hemorrhage class | Blood loss | What you may notice |
Class I | Up to 15% | People generally don't have symptoms. [1] |
Class II | 15% to 30% | Dizziness or lightheadedness, fatigue and weakness, nausea and vomiting, shortness of breath with a faster breathing rate, and an increased heart rate. [1] |
More than 30% | Over 30% | Confusion, seizures, loss of consciousness and hypovolemic shock. [1] |
Call 911 or your local emergency number, or go to the emergency room, if you or someone near you has these symptoms. [1]
Symptoms by body area
Head: thunderclap headache, vision problems, confusion and weakness on one side of the body. [1]
Chest: difficulty breathing, chest pain and coughing up blood. [1]
Abdomen: swelling or a feeling of fullness, abdominal bruising, and bloody vomit, urine or stool. [1]
Bones, joints and muscles: bruising, swelling and pain. Compartment syndrome is a medical emergency. [1]
Causes of internal bleeding
The most common cause of internal bleeding is trauma, such as a vehicle accident or other blunt or penetrating injury. But several other injuries and conditions can cause it. [1]
Gastrointestinal conditions: esophagitis, gastritis, peptic ulcer disease, Crohn's disease, colon polyps, colitis and GI cancers. [1]
Ruptured aneurysms: an aneurysm is a bulge in an artery wall. They are more common in the brain or the aorta, and a rupture can cause severe internal bleeding. [1]
Causes in females: a ruptured ovarian cyst, ectopic pregnancy and postpartum hemorrhage. [1]
Bone fractures: breaking a long or large bone such as the thigh bone (femur) or pelvis can tear blood vessels. [1]
Surgery: in rare cases, bleeding continues after the surgeon closes the incision. [1]
Hemorrhoids: swollen veins in and around the anus and rectum that can cause rectal bleeding. [1]
Viral hemorrhagic fevers: a group of viral infections that can cause uncontrolled bleeding, including Ebola virus disease, Marburg virus disease and dengue fever. [1]
Risk factors
Each cause has its own risk factors. For example, smoking and high blood pressure raise the risk of aneurysms. Two major risk factors for internal bleeding in general are: [1]
Blood disorders: bleeding disorders such as hemophilia make bleeding harder to stop and raise the risk of severe internal bleeding.
Blood-thinning medications: anticoagulants, antiplatelet medications and high doses of NSAIDs can raise the risk of severe internal bleeding if a blood vessel breaks.
Complications
Complications happen because decreased blood flow means organs don't get enough oxygen (tissue hypoxia). This can lead to organ failure, coma and death. [1]
Bleeding inside the skull can cause long-term neurological and cognitive problems. A subarachnoid hemorrhage can lead to vasospasm in brain blood vessels in the following weeks and result in a stroke. Other complications include re-bleeding and hospital-related problems such as deep vein thrombosis (DVT) and infection. [1]
How internal bleeding is diagnosed
Diagnosis means finding where the bleeding is and what's causing it. A healthcare provider will likely use imaging and laboratory tests, do a physical exam and ask about your medical history. [1] In trauma, emergency teams commonly use a quick bedside ultrasound called a FAST exam to look for blood around the heart or abdominal organs, and CT scans help locate the source of the bleeding.
Treatment
Treatment depends on the cause and severity. If the cause is a known underlying condition, such as a gastrointestinal problem, your provider will adjust your treatment plan. If the cause is unknown or the bleeding is severe, you need treatment in a hospital, where the team finds the cause and treats it. You may need: [1]
Surgery
Vitamin K injections (to help stop bleeding)
IV fluids
Blood transfusions
Depending on the source, doctors may also stop bleeding with a catheter-based procedure that blocks the damaged vessel (embolization) or with endoscopy for bleeding in the digestive tract.
Does internal bleeding heal itself?
Minor internal bleeds may heal on their own if you don't have a bleeding disorder or take blood-thinning medication. But it's always a good idea to see your healthcare provider if you have signs of internal bleeding, such as bloody stool or urine, and you don't know the reason, even if it's a small amount. Moderate to severe internal bleeding needs immediate hospital treatment and can be fatal if it isn't treated in time. [1]
Outlook
The outlook depends greatly on how severe the bleeding is and how quickly it is detected and treated. The sooner you get treatment, the better, which is why it's crucial to get medical help right away if you have signs of moderate to severe internal bleeding. [1]
When to get emergency help
Call 911 or your local emergency number, or go to the emergency room, if you or someone near you has lightheadedness, shortness of breath, fatigue, a fast heart rate, confusion, seizures or loss of consciousness, a sudden severe headache, chest pain, or notice blood in poop, pee, spit or vomit. [1]
Frequently Asked Questions
Can internal bleeding stop on its own?
Minor internal bleeds may heal on their own if you don't have a bleeding disorder or take blood-thinning medication. Moderate to severe internal bleeding needs immediate hospital treatment.
How long does it take for internal bleeding to show symptoms?
It depends on how fast the bleeding is. Internal bleeding can be sudden and rapid or slowly build up, so symptoms can appear right away or later.
Is a bruise internal bleeding?
Yes. A bruise is the most common type of visible internal bleeding. Blood vessels under the skin leak, but the skin itself stays unbroken.
What is the most common cause of internal bleeding?
Trauma, such as a vehicle accident or other blunt or penetrating injury, is the most common cause.
Can blood thinners cause internal bleeding?
Anticoagulants, antiplatelet medications and high doses of NSAIDs can raise the risk of severe internal bleeding if a blood vessel breaks. Don't stop a prescribed blood thinner on your own, and ask your doctor about your risk.
What is hypovolemic shock?
Hypovolemic shock is a life-threatening state in which blood volume is too low for the body to circulate blood properly. Losing more than 30% of your blood volume can lead to it.
What is a FAST exam?
FAST stands for Focused Assessment with Sonography for Trauma. It is a quick bedside ultrasound used in emergency care to look for free blood around the heart or abdominal organs.
Can you have internal bleeding without pain?
Yes. Symptoms vary with the location, the severity of the damage and the amount of blood lost, and weakness or lightheadedness can come before significant pain.
What does blood in the stool look like?
Blood in the stool can look bright red or dark and tarry, depending on where in the digestive tract the bleeding is. Any blood in your stool should be checked by a provider.
What is a thunderclap headache?
A thunderclap headache is an extremely severe headache that reaches its peak within about a minute. It is listed as a specific symptom of bleeding in the head and needs emergency care.
How is internal bleeding treated in an emergency?
Hospital care can include surgery, vitamin K injections, IV fluids and blood transfusions while the team finds and treats the cause.
Can a broken bone cause internal bleeding?
Yes. Breaking a long or large bone, such as the thigh bone (femur) or pelvis, can cause internal bleeding if bone fragments tear blood vessels.
What are viral hemorrhagic fevers?
Viral hemorrhagic fevers are a group of viral infections that can cause uncontrolled bleeding, including Ebola virus disease, Marburg virus disease and dengue fever.
What is embolization?
Embolization is a minimally invasive procedure in which a doctor blocks a damaged blood vessel through a catheter to stop it from bleeding.
Why is internal bleeding dangerous for the organs?
Blood loss reduces blood flow to your organs, so they don't get enough oxygen. That can lead to organ failure, coma and death.
Can internal bleeding happen after surgery?
In rare cases, yes. Bleeding can continue after the surgeon closes the incision, and in some of these cases it can be severe.
References
Cleveland Clinic. Internal Bleeding. Cleveland Clinic. Last updated June 12, 2025. https://my.clevelandclinic.org/health/diseases/internal-bleeding
Shakur H, et al. Effects of tranexamic acid on death, vascular occlusive events, and blood transfusion in trauma patients with significant haemorrhage (CRASH-2): a randomised, placebo-controlled trial. Lancet. 2010;376(9734):23-32. PMID 20554319. https://doi.org/10.1016/S0140-6736(10)60835-5
Holcomb JB, et al. Transfusion of plasma, platelets, and red blood cells in a 1:1:1 vs a 1:1:2 ratio and mortality in patients with severe trauma: the PROPPR randomized clinical trial. JAMA. 2015;313(5):471-482. PMID 25647203. https://doi.org/10.1001/jama.2015.12
Medical disclaimer
This article is for general educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. If you think you may have a medical emergency, call your doctor or 911 immediately.
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