The recommended dosage of aspirin for pain in adults and children aged 12 and older is 325 to 650 milligrams taken at 4-hour intervals, according to Drugs.com. Children aged 2 to 11 should take between 10 and 15 milligrams. The maximum daily dosage of aspirin for adults is 4,000 milligrams.
Accidental or intentional ingestion of excessive amounts of aspirin can cause stomach discomfort, queasiness and vomiting, according to MedlinePlus. People who consume aspirin on a continual basis can experience symptoms of chronic aspirin overdose, a condition that occurs when the medication builds up in the system over time. Symptoms of chronic aspirin overdose include heart palpitations, tiredness, lethargy and ringing in the ears.