The purpose of this systematic review is to test the hypothesis that carefully selected low-risk patients with acute pulmonary embolism (PE) can safely be treated entirely as outpatients or after early hospital discharge. Included articles were required to describe inclusion or exclusion criteria and outcome of patients treated for PE. Early hospital discharge was defined as an average hospital stay < or = 3 days. Six investigations included patients with PE who were treated entirely as outpatients; two investigations included patients with PE who were treated after early discharge. All investigations included only low-risk patients or patients with small or medium sized PE. Outcome after 3-46 months in patients treated entirely as outpatients showed recurrent PE in 0% to 6.2% of patients, major bleeding in 0% to 2.8% with one death from an intracerebral bleed. Definite death from PE did not occur, but there was one possible death from PE. Outcome in three months in patients treated after early discharge showed no instances of recurrent PE. Major bleeding occurred in 0% to 3.7% of patients. There were no deaths from PE, but there was one death from bleeding. In conclusion, outpatient therapy of acute PE is probably safe in low-risk, carefully selected compliant patients who have access to outpatient care if necessary. Such outpatient treatment would be cost-effective.