Non-steroidal anti-inflammatory drugs (NSAIDs) can irritate the stomach and digestive tract and, in some people, can contribute to ulcers or gastrointestinal bleeding. Examples of NSAIDs include ibuprofen, naproxen, diclofenac and aspirin when it is used for pain or inflammation. Stomach or intestinal bleeding is a serious possible side effect, although most people who use an NSAID will not experience it.
Possible warning signs include vomiting blood, vomit that looks like coffee grounds, black or tar-like stools, blood in the stool, persistent or severe stomach pain, unusual weakness, pale skin, dizziness or feeling faint. Bleeding can sometimes develop without obvious warning symptoms, so new or concerning symptoms during NSAID treatment deserve attention.
If you are vomiting blood, passing black tar-like or bloody stools, feeling faint or becoming rapidly unwell, seek urgent medical attention rather than trying to manage the problem yourself.
This page focuses specifically on possible NSAID-related stomach bleeding. For other medicine-related symptoms, see the Symptom-Led Side Effects hub or the related parent guide.
How NSAIDs Stomach Bleeding Symptoms can be linked to medicines or supplements
NSAIDs reduce pain, inflammation and fever by interfering with substances called prostaglandins. Some prostaglandins also help protect the lining of the stomach and intestines. Reducing this protection can make the digestive tract more vulnerable to irritation, ulcers and, less commonly, serious bleeding.
NSAID-related gastrointestinal complications can occur during treatment even in someone who has not previously noticed indigestion or other stomach symptoms. Official medicine guidance warns that ulcers and bleeding can occur at any point during NSAID use and may sometimes happen without warning.
This is different from the milder digestive side effects that NSAIDs can cause. Indigestion, stomach ache, nausea and diarrhoea are recognised NSAID side effects, but these symptoms do not by themselves prove that gastrointestinal bleeding is occurring.
Possible medicine categories
Products that may be relevant when investigating possible medicine-related stomach bleeding include:
- NSAID painkillers, including medicines containing ibuprofen, naproxen or diclofenac.
- Aspirin-containing products. Aspirin can increase bleeding risk, particularly when combined with other medicines that affect bleeding.
- Combination pain or cold-and-flu products. Some products contain an NSAID alongside other ingredients, so it is possible to take more than one NSAID-containing medicine without immediately realising it.
- Medicines that affect blood clotting, such as anticoagulants, which can increase the seriousness or likelihood of bleeding when combined with an NSAID.
- Corticosteroids and certain other medicines. Some combinations can increase gastrointestinal bleeding risk and should be reviewed by a healthcare professional.
Herbal products and supplements also matter when reviewing a suspected reaction because some can affect bleeding or interact with medicines. Tell your pharmacist or doctor about all prescription medicines, over-the-counter products, vitamins and supplements you use rather than assuming a non-prescription product is irrelevant.
Timing clues
Timing can help a healthcare professional assess whether a medicine might be involved, although timing alone cannot diagnose the cause.
Useful questions include:
- Did the symptoms begin after starting an NSAID?
- Did they appear after using the medicine more frequently or for longer?
- Have you recently added another painkiller or anti-inflammatory medicine?
- Did symptoms start after another prescription medicine or supplement was added?
- Have you previously experienced an ulcer or gastrointestinal bleeding while taking an NSAID?
- Did indigestion, stomach discomfort or nausea appear before more concerning symptoms?
Serious gastrointestinal complications can occur even with relatively short NSAID use, while risk may increase with higher exposure or longer treatment. Never use timing alone to decide that bleeding is harmless.
Medicines and product categories that may be associated with this symptom
When stomach bleeding is suspected, the important question is not simply whether a particular medicine appears on a list. The combination of the medicine, your other treatments, your medical history and your current symptoms all matters.
NSAIDs are widely used for conditions such as headaches, muscle or joint pain, menstrual pain, injuries and inflammatory conditions. Some are available without a prescription, while others require a prescription depending on the medicine, strength and local regulatory requirements.
Certain factors are associated with a higher risk of NSAID-related ulceration or bleeding. These include a previous stomach ulcer or gastrointestinal bleed, older age, longer NSAID use, higher doses, smoking, alcohol use, bleeding disorders and taking medicines such as anticoagulants or corticosteroids. Some NSAID medicine guides also identify SSRIs and SNRIs as medicines that may increase gastrointestinal bleeding risk when used alongside NSAIDs.
Having one of these factors does not mean that bleeding will occur. It does mean that a doctor or pharmacist may need to consider the overall risk more carefully.
Priority related pages
If your concern is broader than stomach bleeding, use the guide that most closely matches what you are experiencing:
- See serious medication side effects if you are trying to identify other potentially dangerous reactions.
- See when to see a doctor for medication side effects for general guidance about symptoms that warrant medical assessment.
- Browse medication side effects if you need general medicine-safety information rather than information specifically about gastrointestinal bleeding.
These guides can help you organise your questions, but they cannot determine the cause of bleeding or replace an examination by a healthcare professional.
How to choose the right next guide
If your main symptom is vomiting blood, black tar-like stool or visible blood in your stool, prioritise medical assessment rather than continuing to compare side-effect pages.
If your symptoms are primarily indigestion, mild stomach discomfort or nausea without signs of bleeding, a pharmacist or doctor can help determine whether your medicine may be irritating your digestive tract and whether your treatment needs review.
If you are taking several medicines or supplements, focus on getting the complete combination reviewed. Do not assess each medicine in isolation because interactions and overlapping ingredients can change the risk.
Red flags: when this symptom may need urgent medical attention
Gastrointestinal bleeding can become serious and should not be diagnosed or managed from symptoms alone.
Seek urgent medical help if you experience:
- vomiting bright red blood
- vomit that is dark or resembles coffee grounds
- black, sticky or tar-like stools
- obvious blood in your stools
- fainting or feeling close to fainting
- severe or rapidly worsening abdominal pain
- marked dizziness, weakness, confusion or collapse
- pale, cold or clammy skin together with suspected bleeding
- rapid or shallow breathing while feeling seriously unwell.
Vomiting blood is a recognised sign of bleeding in the upper digestive tract, while black tar-like stool can indicate digested blood from higher in the gastrointestinal tract. These symptoms have several possible causes, so NSAIDs should not automatically be assumed to be responsible.
Other serious medicine reactions also require immediate help. Trouble breathing, swelling of the face, tongue or throat, a severe rash, seizures, chest pain, severe bleeding, suspected overdose or rapidly worsening symptoms should be treated as urgent.
Possible medicine categories
If serious bleeding is suspected, tell the healthcare team about all medicines you have recently used, particularly:
- NSAID painkillers
- aspirin-containing medicines
- anticoagulants or other medicines that affect clotting
- corticosteroids
- antidepressants or other medicines your doctor has prescribed
- combination cold, flu or pain products
- complementary medicines, herbal remedies and supplements.
Do not assume that an over-the-counter medicine is unimportant simply because it was purchased without a prescription.
Timing clues
When seeking medical care, be ready to explain when the bleeding or other symptoms started and when you last took your medicines. If possible, take the medicine packaging or an accurate list with you.
Do not delay urgent care while trying to establish whether a particular dose caused the problem.
For broader guidance on recognising high-risk reactions, see serious medication side effects and when to see a doctor for medication side effects.
What to track before speaking to a doctor or pharmacist
If you are medically stable and do not have emergency warning signs, recording a short medicine-and-symptom timeline can make a consultation more useful.
Write down:
- the name of each medicine, including brand and active ingredient if known
- whether each medicine was prescribed or bought over the counter
- when you started taking it
- when the symptoms began
- whether symptoms occur after taking the medicine
- any recent changes in how the medicine has been used
- other prescription medicines, over-the-counter products and supplements
- any previous history of stomach ulcers or gastrointestinal bleeding
- relevant symptoms such as stomach pain, heartburn, nausea, dizziness, unusual tiredness or changes in stool
- whether you have noticed vomit or stool containing blood or appearing unusually dark.
Bring the medicine packet, patient information leaflet or a photograph of the label if that makes it easier to identify exactly what you have taken.
Red-flag symptoms
Do not spend time keeping a detailed symptom diary before seeking help if you have signs of significant bleeding.
Vomiting blood, black tar-like stool, visible blood in the stool, fainting, rapidly worsening weakness or severe abdominal pain need prompt medical assessment.
The same applies if you develop difficulty breathing, swelling of your face or throat, seizures, severe rash, chest pain, collapse or symptoms of an overdose.
When to contact a doctor, pharmacist, or emergency service
A pharmacist can be a useful first point of contact for non-emergency questions about NSAID ingredients, duplicate medicines, interactions and expected digestive side effects.
A doctor should assess persistent, worsening or unusual symptoms, particularly if you have a history of ulcers or gastrointestinal bleeding or use other medicines that increase bleeding risk.
An emergency service or emergency department is appropriate when there are signs of active or serious bleeding, fainting, collapse, breathing difficulties or other severe symptoms.
What not to do without medical advice
Suspected medicine side effects can tempt people to make several treatment changes at once. That can make the situation harder to assess and, in some circumstances, create additional risk.
Do not:
- make major changes to prescription treatment without speaking to an appropriate healthcare professional
- take extra NSAIDs to control pain without checking whether another medicine already contains an NSAID
- combine different anti-inflammatory painkillers simply because they have different brand names
- assume black stools are harmless when they occur alongside symptoms suggesting gastrointestinal bleeding
- ignore vomiting blood because it happened only once
- rely on food, antacids or home remedies to treat suspected internal bleeding
- delay urgent medical attention while waiting to see whether serious symptoms disappear
- conceal supplements, alcohol use or non-prescription medicines from the healthcare professional assessing you.
If you take a medicine regularly for an important medical reason, get individual advice about what to do next. For example, NHS guidance for people regularly taking low-dose aspirin specifically advises continuing it unless a healthcare professional tells them to stop.
Possible medicine categories
Pay particular attention to duplicate products. An NSAID may be sold as a stand-alone painkiller or included in a combination product, so checking the active ingredients is more useful than checking only brand names.
If you are unsure what a product contains, show the packaging to a pharmacist.
Timing clues
If a healthcare professional asks when symptoms occurred, give the most accurate timeline you can rather than changing your medicines repeatedly to “test” whether symptoms return.
A suspected gastrointestinal bleed is not something to reproduce intentionally to establish whether a medicine is responsible.
Related side-effect guides and reporting options in South Africa
Medicine-related gastrointestinal bleeding is a safety issue, not something that should be diagnosed from a search result. Use this guide to recognise warning signs, gather useful information and decide when professional assessment is needed.
For broader symptom navigation, visit the Symptom-Led Side Effects hub. For general medicine information, see medication side effects.
If you or a healthcare professional suspects an adverse reaction, it may also be appropriate to report side effects in South Africa. SAHPRA maintains adverse-drug-reaction reporting processes as part of post-marketing medicine safety monitoring, and its reporting documentation covers medicines as well as relevant health products, including herbal products.
Reporting a suspected reaction is separate from obtaining medical treatment. If you have symptoms of active bleeding or another emergency, seek medical care first.
What information to record
Useful details for a suspected side-effect report can include:
- the medicine or product name
- the active ingredient, if known
- when the medicine was started
- when the suspected reaction occurred
- other medicines and supplements being used
- a clear description of what happened
- whether medical treatment was required.
Keep packaging or medicine information available where possible, as this can help identify the correct product.
Where reporting fits into medicine safety
Adverse-event reporting helps regulators monitor medicine safety after products are in use. A report does not by itself prove that a medicine caused an event, but reports can contribute to the broader evidence used to identify potential safety signals.
In South Africa, SAHPRA provides adverse-drug-reaction reporting guidance and reporting forms for medicine-safety monitoring.
Frequently asked questions
Is stomach bleeding a common side effect of NSAIDs?
Digestive symptoms such as indigestion and stomach ache are recognised NSAID side effects. Stomach or intestinal ulcers and bleeding are more serious complications and are less common, but they can occur and may sometimes develop without obvious warning symptoms.
Your individual risk depends on factors such as your medical history, age, other medicines and how the NSAID is being used.
How long can NSAID stomach bleeding symptoms last?
There is no safe standard duration to wait out suspected gastrointestinal bleeding. How long symptoms last depends on the cause, location and severity of the bleeding and whether treatment is needed.
Vomiting blood, passing black tar-like stool, visible blood in the stool, fainting or rapidly worsening symptoms require prompt medical assessment rather than waiting for the symptoms to resolve.
Should I stop the medicine?
Do not make unsupervised changes to important prescription treatment based solely on an online article. What to do depends on the medicine, why you take it and how serious your symptoms are.
If you suspect a non-emergency side effect, contact a pharmacist or doctor promptly for personalised advice. If you have signs of serious bleeding or another medical emergency, seek immediate medical attention.
When should I seek help?
Seek urgent medical care for vomiting blood, black tar-like or bloody stools, fainting, severe abdominal pain, collapse or rapidly worsening illness. Trouble breathing, swelling of the face or throat, seizures, chest pain, severe rash, severe bleeding or suspected overdose also require urgent help.
For symptoms that are persistent or concerning but not immediately severe, speak to a doctor or pharmacist.
What are the most important things to know about NSAIDs stomach bleeding symptoms?
NSAIDs can cause ulcers and gastrointestinal bleeding, and serious problems may occasionally occur without earlier stomach symptoms.
The most important warning signs are vomiting blood, coffee-ground-like vomit, black tar-like stools, blood in the stool, severe abdominal pain, marked weakness, dizziness or fainting.
Do not diagnose the cause yourself. Keep a record of your medicines and symptoms, check for duplicate NSAID-containing products, and speak to a pharmacist or doctor when concerned. Seek urgent medical attention for severe bleeding, rapidly worsening symptoms, allergic reactions, overdose concerns, or serious symptoms involving a child, an older adult or pregnancy.
Medical safety note
This information is for general education and does not diagnose gastrointestinal bleeding or establish that an NSAID caused your symptoms. Different medical conditions and medicines can cause similar symptoms. A doctor or pharmacist can assess your individual medicines, medical history and risks.
If you are vomiting blood, passing black tar-like or bloody stools, fainting, having severe abdominal pain, struggling to breathe or becoming rapidly unwell, seek urgent medical help.