['The purpose of the study was to determine if early mobilisation in patients with acute lower limb deep vein thrombosis (DVT) increases the incidence of symptomatic pulmonary embolism (PE) and to evaluate the predisposing factors for PE such as location of the thrombus and duration of symptoms.', 'The current study was a prospective randomised clinical trial. Between January 2005 and December 2007, 219 patients with acute lower limb DVT were enrolled in the study (118 males and 101 females); the mean age was 64.2 years.', '<15 days of initial symptoms, life expectancy >1 year, no life-threatening clinical conditions, and signed informed consent. The patients were randomised into two groups. Group A, 105 patients (47.9%) were hospitalized and received 5 days of bed rest; Group B, 114 patients (52.1%) received care at home with early walking and compression stockings. The primary end point was the presence of symptomatic PE during the first 10 days of treatment. The relationships between the duration of symptoms, location of the thrombus, and symptomatic PE were also analysed.', 'Five cases of symptomatic PE were detected (2.3%), three in Group B and two in Group A. There was no significant difference in the occurrence of new PE between the two groups (P=0.54). Likewise, no difference was detected based on the duration of symptoms (P=0.62) and the location of the thrombus (P=0.43).'] Does early mobilisation in patients with acute deep vein thrombosis increase the risk of a symptomatic pulmonary embolism?