Patients with acute ischaemic stroke should receive intravenous thrombolysis with 0.9 mg/kg of recombinant tissue plasminogen activator as quickly as possible. In order to reduce the door-to-needle time, many physicians estimate the patient's body weight. However, these estimates are frequently inaccurate and inaccuracy can lead to dosage errors. According to a meta-analysis in a Cochrane study, the risk of developing intracranial haemorrhage is almost tripled for patients treated with higher thrombolytic doses, compared with patients receiving a dosage based on accurate weight measurements (odds ratio: 2.71). Only 28% of physicians estimate to within 5 kilograms of actual body weight. In order to reduce the risk of complications, patients arriving at the emergency room should be weighted with a scale. Alternatively, the body weight can be estimated using a validated nomogram.