Most healthy adults can take 325 mg to 1000 mg of acetaminophen every 4 to 6 hours as needed for pain or fever. The total daily amount should usually not exceed about 3,000 to 4,000 mg in 24 hours. Staying within this range helps reduce the risk of serious side effects.
The main reason for this limit is that high doses can harm the liver. Taking more than recommended, or taking several medicines that contain acetaminophen at the same time, increases the chance of accidental overdose. Many cold, flu, and pain products already contain acetaminophen, so it is important to check medication labels carefully.
Some people may need lower doses. Older adults, people who weigh less than about 110 pounds, or those with liver disease or heavy alcohol use may be advised to take smaller amounts. In these cases, a healthcare professional may recommend a lower daily limit to reduce the risk of liver injury.
When using acetaminophen, follow the instructions on the label and avoid combining multiple products that contain the same ingredient. If pain or fever lasts more than a few days, or if there is uncertainty about the correct dose, it is best to speak with a primary care doctor or pharmacist before continuing treatment.