What will happen if you don't treat an ulcer? Key risks and complications

September 28, 2025 •

4 min read

An estimated 6% of Americans are diagnosed with peptic ulcers each year. While many ignore the initial discomfort, failing to seek treatment can transform a manageable issue into a life-threatening health crisis. Understanding what will happen if you don't treat an ulcer is critical for your health.

Quick Summary

Ignoring an ulcer allows stomach acid to continue eroding the digestive lining, potentially causing severe complications such as internal bleeding, a ruptured stomach wall (perforation), or a dangerous blockage. These issues can rapidly become life-threatening and require immediate medical attention.

Key Points

Internal Bleeding: Ignoring an ulcer can cause it to erode into blood vessels, leading to slow blood loss (anemia) or a sudden, severe hemorrhage.
Perforation: Left untreated, an ulcer can create a hole in the stomach or intestinal wall, causing a life-threatening infection called peritonitis.
Obstruction: Swelling and scarring from a chronic ulcer can block the passage of food, leading to persistent vomiting and weight loss.
Increased Cancer Risk: Chronic inflammation from an H. pylori-related ulcer significantly increases the long-term risk of stomach cancer.
Emergency Signs: Seek immediate medical care if you experience coffee-ground vomit, black tarry stools, or severe, sharp abdominal pain.

The Progression of Untreated Ulcers

An ulcer, a painful open sore in the lining of the stomach or upper small intestine (duodenum), doesn't typically get better on its own. Instead, it can worsen over time as stomach acid continues to erode the protective mucosal layer. This ongoing damage can lead to a cascade of serious and potentially fatal complications that make initial symptoms, like burning abdominal pain, seem minor in comparison.

Internal Bleeding: The Most Common Complication

Internal bleeding is the most frequent and potentially life-threatening complication of an untreated ulcer. As the sore eats deeper into the digestive wall, it can damage underlying blood vessels. The bleeding can manifest in two ways:

Slow, Chronic Bleeding: This can go unnoticed for a long time but leads to anemia due to a gradual loss of red blood cells. Symptoms of anemia include persistent fatigue, weakness, shortness of breath, and pale skin.
Rapid, Severe Hemorrhage: A sudden, large bleed is a medical emergency. Signs include vomiting blood (which can appear bright red or like dark coffee grounds) and passing black, tarry, or sticky stools. This can cause a sudden drop in blood pressure, leading to dizziness, fainting, or shock.

Perforation: A Medical Emergency

Perforation occurs when an ulcer eats a complete hole through the wall of the stomach or duodenum. This allows bacteria and partially digested food to leak into the abdominal cavity, a sterile space, and cause a severe, widespread infection called peritonitis. This is a surgical emergency with a high mortality rate if not treated immediately.

Symptoms of a perforated ulcer include:

Sudden, severe, and sharp abdominal pain that may radiate to the back or shoulder.
A rigid, board-like abdomen that is tender to the touch.
Nausea and vomiting.
Fever and chills.
Rapid heart rate.

Gastric Outlet Obstruction: Preventing Digestion

Long-standing inflammation and scarring from an untreated ulcer can cause the opening between the stomach and small intestine (the pylorus) to swell and narrow. This condition, known as gastric outlet obstruction, blocks the passage of food from the stomach. This blockage can lead to chronic issues with digestion and nutrition.

Symptoms of obstruction include:

Recurrent, persistent nausea and vomiting, often of undigested food.
Feeling of fullness after eating only a small amount of food (early satiety).
Bloating and abdominal pain.
Unexplained weight loss.

The Connection to Stomach Cancer

While not all ulcers lead to cancer, there is a clear link, particularly when the ulcer is caused by a chronic Helicobacter pylori (H. pylori) infection. The persistent inflammation caused by the bacteria over decades can alter the cells of the stomach lining, increasing the risk of stomach cancer. Studies have shown that eradicating the H. pylori infection early can significantly decrease this risk.

Comparing the Outcomes: Treated vs. Untreated Ulcers


Feature	Treated Ulcer	Untreated Ulcer
Symptom Resolution	Symptoms typically resolve completely with proper medication and lifestyle changes.	Symptoms persist, worsen, and eventually lead to severe complications.
Complications	The risk of serious complications is very low with adherence to treatment.	High risk of internal bleeding, perforation, obstruction, and cancer.
Healing Process	Medications reduce stomach acid and allow the ulcer to heal, often within a few weeks.	Ulcer continues to deepen, causing more extensive damage and scarring.
Long-Term Prognosis	Excellent prognosis, especially with eradication of H. pylori.	Poor prognosis, with significant risk of surgery, life-threatening events, and chronic health issues.
Medical Intervention	Outpatient treatment with medication and follow-up.	Potential for emergency surgery, blood transfusions, and prolonged hospitalization.

Long-Term Prevention and Management

Preventing the recurrence of ulcers is a critical part of treatment, especially after experiencing complications. For H. pylori-related ulcers, completing the full course of antibiotics is essential to eradicate the bacteria permanently. For NSAID-induced ulcers, avoiding these drugs or using alternative pain relief methods is necessary.

Beyond medication, lifestyle adjustments play a significant role. Quitting smoking, which hinders ulcer healing, and limiting alcohol consumption, which can irritate the stomach lining, are vital steps. For more detailed information on peptic ulcers and their treatment, consult the Mayo Clinic resource.

Conclusion: A Clear Path Forward

Ignoring an ulcer is a dangerous gamble with your health. The minor discomfort of a new ulcer can quickly escalate into a medical crisis involving internal bleeding, perforation, or obstruction. Beyond immediate dangers, chronic, untreated ulcers can increase your risk of developing stomach cancer. The good news is that most ulcers are highly treatable with modern medicine, especially if caught early. Taking the initial symptoms seriously and seeking medical help is the most effective way to prevent these grave consequences and ensure a full recovery.

Frequently Asked Questions

The first signs often include a worsening or more persistent burning pain in the abdomen, along with new symptoms like nausea, bloating, feeling full quickly, or changes in your appetite.

As an ulcer deepens, it can erode into a blood vessel in the stomach or duodenal wall, leading to either slow, chronic blood loss (causing anemia) or a sudden, severe hemorrhage.

While some ulcers may temporarily seem to improve, they rarely heal completely without proper medical treatment, especially if the underlying cause like H. pylori infection or NSAID use is not addressed. Ignoring it greatly increases the risk of recurrence and severe complications.

A perforated ulcer is a hole that has formed in the wall of the stomach or intestine. It is dangerous because it allows bacteria and digestive contents to spill into the abdominal cavity, causing a severe, life-threatening infection called peritonitis.

Yes, particularly if the ulcer is caused by a long-term H. pylori infection. The chronic inflammation can lead to cellular changes in the stomach lining over time, which increases the risk of developing stomach cancer.

You should go to the emergency room immediately if you have signs of severe bleeding (vomiting blood or coffee-ground material, black or tarry stools) or perforation (sudden, severe abdominal pain, rigid abdomen).

After complications arise, doctors may use an upper endoscopy to visualize the digestive tract and stop any bleeding. CT scans or X-rays can be used to detect perforations, and blood tests can check for anemia or infection.