An aspirin overdose can occur after a single large dose (this is called an acute overdose) or develop gradually after taking lower doses for a long time (this is called a chronic overdose). An acute aspirin overdose may be accidental or intentional. A toxic dose of aspirin for a human adult is considered to be 200 to 300 milligrams per kilogram of body weight (works out to be 13,600 to 20,400mg of aspirin for a person who weighs 68 kg [approximately 150 pounds]). A dose of 500 milligrams per kilogram of body weight (34,000mg for a 68kg person) is considered a potentially lethal dose of aspirin, and could result in death.