For adults buying ibuprofen over the counter, the standard dose is 200 to 400 mg every four to six hours, with a maximum of 1,200 mg (six 200 mg tablets) in 24 hours. That ceiling applies to self-treatment without a doctor’s guidance. Prescription-strength ibuprofen can go higher, but those doses come with closer medical supervision and increased risk of side effects.
Single Dose and Daily Limits for Adults
Over-the-counter ibuprofen tablets are typically 200 mg each. The FDA label directs adults and children 12 and older to start with one tablet every four to six hours. If one tablet doesn’t relieve pain or fever, you can take two (400 mg) per dose. The hard rule: no more than six tablets (1,200 mg) in a 24-hour period unless a doctor tells you otherwise.
Under medical supervision, prescription doses can reach 800 mg per dose and up to 3,200 mg per day for conditions like rheumatoid arthritis or severe inflammation. These higher doses carry a meaningfully greater risk of stomach bleeding, kidney stress, and cardiovascular problems, which is why they require ongoing monitoring.
The general principle on the FDA label is worth remembering: use the smallest effective dose for the shortest time needed. If 200 mg handles your headache, there’s no benefit to taking 400.
Dosing for Children
Children’s doses are calculated by weight, not age. The standard range is 4 to 10 mg per kilogram of body weight per dose, given every six to eight hours. A single dose should never exceed 400 mg, and the total daily amount should stay under 40 mg per kilogram, up to a maximum of 1,200 mg per day. For children under 12, a pediatrician should guide the dosing rather than relying on adult guidelines.
How Long You Can Take It
The OTC label sets a clear boundary: no more than 10 consecutive days for pain. If your symptoms aren’t improving within that window, something else may be going on that ibuprofen won’t fix. For fever, the timeline is even shorter at three days. These limits exist because the longer you take ibuprofen, the more it stresses your stomach lining and kidneys.
Why the Limits Exist
Ibuprofen works by blocking enzymes called COX-1 and COX-2, which your body uses to produce chemicals that trigger pain, inflammation, and fever. The problem is that those same enzymes also help protect your stomach lining and maintain blood flow to your kidneys. Blocking them relieves pain but simultaneously removes some of your body’s built-in protection for those organs.
That trade-off is manageable at low doses for short periods. At higher doses or over longer stretches, the risks compound. The FDA requires a warning on every ibuprofen label stating that NSAIDs (the drug class ibuprofen belongs to) increase the risk of heart attack, heart failure, and stroke, and that the risk rises with higher doses and longer use.
Stomach and Kidney Risks
Stomach bleeding is the most common serious side effect. Your risk is higher if you’re over 60, have a history of ulcers, take blood thinners or steroids, use other pain relievers containing NSAIDs (like aspirin or naproxen), or drink three or more alcoholic beverages a day.
Kidney damage is most likely in people who already have reduced kidney function, heart failure, diabetes, or high blood pressure, and in those taking blood pressure medications like ACE inhibitors or diuretics. Dehydration amplifies the risk significantly. If you’re sick with vomiting or diarrhea, or you’ve just finished a long endurance event, your kidneys are already under stress, and ibuprofen can tip them further.
Liver injury is far rarer but tends to show up at prescription-level doses of 2,400 to 3,200 mg daily, particularly in people with pre-existing liver disease or those combining ibuprofen with other medications that stress the liver. Elderly patients face heightened risk across all these categories due to naturally declining organ reserve and the likelihood of taking multiple medications.
What Overdose Looks Like
Toxicity data gives useful context for why the dose limits are set where they are. At doses under 100 mg per kilogram of body weight, most people experience no symptoms at all. For a 70 kg (154 lb) adult, that’s about 7,000 mg, well above the daily OTC limit but still unlikely to cause serious harm in a single incident. Between 100 and 300 mg per kilogram, mild stomach and neurological symptoms like nausea, vomiting, and drowsiness appear. Above 300 mg per kilogram, there’s risk of multi-organ damage, and fatalities have been reported at that level.
These numbers don’t mean taking 5,000 mg in a day is safe. Chronic overuse at lower amounts can cause cumulative damage to the stomach, kidneys, and cardiovascular system that a single-dose toxicity threshold doesn’t capture. The OTC ceiling of 1,200 mg per day is set conservatively to protect against both acute harm and the damage that builds over days of use.
People Who Should Use Less or None
Some people need to treat ibuprofen’s standard dose as their upper limit, or avoid the drug entirely. This includes anyone with chronic kidney disease, active stomach ulcers, uncontrolled high blood pressure, or heart failure. People who are dehydrated, those with a single kidney, and organ transplant recipients also face amplified risks at doses other adults tolerate fine.
If you take blood thinners, corticosteroids, or other NSAIDs (including low-dose aspirin for heart protection), adding ibuprofen multiplies your chance of stomach bleeding. Combining it with blood pressure medications can also blunt those drugs’ effectiveness while increasing kidney strain. In these situations, acetaminophen is often a safer alternative for pain relief, though it comes with its own limits.