July 7, 2026, 11:16 am | Read time: 6 minutes
Almost everyone has ibuprofen, acetaminophen, and aspirin at home. But few know what they can really do to the body when taken without caution. While an overdose of acetaminophen can lead to fatal liver failure, improper use of ibuprofen risks stomach ulcers, kidney damage, or heart problems. A pain medication expert tells FITBOOK which pill helps when, how much you should take per day, and why aspirin is an absolute no-go for minors.
Ibuprofen or Acetaminophen? A Guide for Everyday Decisions
Many pain relievers are approved for the same symptoms (such as headaches or toothaches), but they work in completely different ways in the body. Pain specialist Prof. Dr. Stefan Wirz highlights the crucial distinction: anti-inflammatory effects. The head of the Department of Anesthesiology, Interdisciplinary Intensive Care, Pain Medicine/Palliative Medicine – Center for Pain Medicine at Cura Hospital Bad Honnef advises asking this question first: Is the pain accompanied by inflammation (throbbing, swelling) or not?
“Ibuprofen is particularly effective for inflammatory pain, such as arthritis, while acetaminophen is less anti-inflammatory but generally relieves tissue pain,” he explains the key difference.
For everyday use, this means: For uncomplicated headaches or fever, acetaminophen is an option, although studies show it helps better with tension headaches than, for example, back pain. However, for toothaches, migraines, or rheumatic complaints, ibuprofen is often the more effective choice. But where exactly are the limits when taking painkillers?
Pain Expert: “I Observe Application Errors Almost Daily in the Clinic”
“I see application errors with painkillers almost daily in our pain ward and pain clinic,” says Wirz. He attributes this to the over-the-counter availability of pain medications–“and the fact that until a few years ago, pain medicine was not part of medical training, so knowledge gaps still exist.” The expert emphasizes that despite their availability, caution is advised. Both ibuprofen and acetaminophen should be taken without medical advice for no more than a week.1
Expert on Maximum Dosages for Ibuprofen, Acetaminophen, and Aspirin
The expert recommends as a personal guideline to take these medications for no more than a week without consulting a doctor to avoid long-term damage. Wirz warns: “Generally, damage can occur even in healthy individuals if the maximum dose is exceeded and with long-term use.”
Ibuprofen – max. 1200 to 2400 mg per day
“The maximum daily dose for ibuprofen is 1200 to 2400 milligrams,” the expert explains. Consistently overdosing not only risks stomach ulcers but also serious damage to the kidneys and cardiovascular system. Why is this? Overdosing damages the mucous membrane of the gastrointestinal tract, leading to the mentioned dangers. Damage to the inner walls of blood vessels is also a threat, potentially leading to thrombosis, pulmonary embolism, heart attacks, or strokes.
Acetaminophen – max. 4 g per day
For acetaminophen, the therapeutic range is even narrower: According to Wirz, the maximum daily dose of four grams should not be exceeded for patients weighing more than 50 kilograms and without additional illnesses. “Acetaminophen is only weakly pain-relieving for most people and potentially liver-damaging,” he clarifies.
Does the effectiveness of painkillers depend on body position?
Studies show that the active ingredient is absorbed significantly faster by the body when lying on the right side.2 What does the expert say? “This is not entirely certain, but understandable.”
Aspirin – max. once 1000 mg per day
With aspirin (acetylsalicylic acid), there is also a dangerous dosage trap that is often underestimated, says Wirz. While the active ingredient is classically used for the acute treatment of migraines–here Prof. Wirz mentions a dose of 1000 milligrams as a single dose per day–he strongly warns against the risks of long-term or careless use. The greatest danger, as with ibuprofen, lies in the mucosal-damaging effect, with the risk of, for example, stomach ulcers.
Better to take before, during, or after a meal?
It is best to take with plenty of fluids and during or after a meal. Taking it after meals may delay the onset of action, but it prevents excessive stomach irritation.
Overview
Can I combine aspirin, paracetamol, and ibuprofen?
What Parents Should Know When Their Baby Has a Fever
These Side Effects Threaten the Heart, Liver, and Kidneys
The seemingly harmless painkillers pose significant risks when used improperly. Each active ingredient has its own weaknesses for the internal organs. The pain specialist is particularly critical of the use of acetaminophen concerning the number one detoxification organ: “Acetaminophen is liver-damaging and can lead to fatal liver failure if overdosed.”
While the liver is the focus with acetaminophen, ibuprofen and aspirin primarily attack the body’s filtration function with prolonged use, explains Stefan Wirz. He warns that regular use of these substances “regularly leads to kidney damage” as well as injuries to the gastrointestinal mucosa.
The preparations are also potentially harmful to the cardiovascular system. The expert particularly cautions against ibuprofen: “Ibuprofen should not be used in cases of heart failure and circulatory diseases, as it has negative effects on the vascular system.” With long-term use, the active ingredient is potentially harmful to the entire cardiovascular system.
Moreover, long-term use of ibuprofen can lead to damage to the inner walls of blood vessels, “up to possible thrombosis, pulmonary embolism, heart attacks, or strokes,” Wirz explains.
When taking aspirin to improve blood clotting in heart disease or after a stroke, additional use as a pain reliever has more disadvantages than advantages.
Therefore, anyone with pre-existing heart, liver, or kidney conditions should use painkillers with extreme caution and only after consulting a doctor.
Also interesting: How dangerous is it to take painkillers before exercising?
No-Gos: What You Should Never Do
Aspirin should never be used in children and adolescents under 18 years old if they have febrile or viral illnesses. Prof. Wirz warns of the life-threatening Reye’s syndrome, a rare but severe complication.
Do Not Combine Active Ingredients Arbitrarily
Equally critical is the arbitrary combination of active ingredients in everyday life. The expert makes it clear: “Combining ibuprofen and aspirin is not sensible.” This is partly because ibuprofen can inactivate the effect of low-dose aspirin taken to prevent heart attacks. The simultaneous intake of ibuprofen and acetaminophen should also be avoided without medical supervision, as the specific effectiveness in private use is difficult to assess.
Who Should Completely Avoid Ibuprofen
Another strict no-go is ignoring pre-existing conditions and maximum doses. Those with heart failure or circulatory diseases should avoid ibuprofen, as it negatively affects the vascular system. Similarly, the maximum daily dose–for acetaminophen, about four grams for adults over 50 kilograms–should never be exceeded, as otherwise, fatal liver failure may occur.