Standard treatment for complicated parapneumonic effusion is antibiotic therapy and drainage of the infected pleural fluid. Complicated effusions refractory to standard treatment require further interventions such as intrapleural fibrinolysis. This is effective for patients with loculated effusions as local fibrinolytics administered via a chest drain can break down the septations. Common complications include intrapleural bleeding, hypersensitivity, pain and discomfort with fibrinolytics, but no studies, to our knowledge, have reported pericardial haemorrhage. In this case report, we describe a 75-year-old female who presented with dyspnoea, mucopurulent cough and intermittent fever. She was diagnosed with community-acquired pneumonia. A chest radiograph revealed pleural effusion suggestive of parapneumonic effusion. Further computed tomography (CT) imaging showed a complicated parapneumonic effusion with loculations that were drained by an ultrasound-guided chest drain. As there was inadequate drainage, local fibrinolytics were administered. On the third administration of alteplase and dornase alfa, the patient deteriorated with a drop in haemoglobin and presented with muffled heart sounds, jugular venous distension, and low-normal systolic blood pressure (Beck's triad). A clinical suspicion of pericardial effusion was made and confirmed by echocardiography. CT imaging revealed a high-density effusion as measured with the Hounsfield Unit, supporting the likelihood of a haemorrhagic pericardial effusion. Subsequently, the patient was stabilised with conservative management, close observation, and input from the intensive treatment unit team. In conclusion, we report pericardial haemorrhage as a rare complication of local fibrinolytic therapy that can be managed conservatively.