We report on a 15-year-old girl who presented with a history of chest pain, coughing, intermittent haemoptysis, fever, pallor and vomiting to a rural hospital in Tanzania. She was severely anaemic with signs of cardiorespiratory distress. Haemoglobin was 4.8 g/dl; the chest X-ray film was normal. She required one unit of blood. After 3 days, she vomited up a small parasite which proved to be an aquatic leech. Oesophagogastroscopy, then performed, revealed four small mucosal lesions in the pharynx and upper oesophagus. No other leeches were seen. Further oesophagogastroscopy 4 days later showed a normal mucosa. The girl was discharged on iron and folic acid supplements. A small lake near her village was identified as the likely source of her infestation. The family had used the water for drinking without any precautions—Terrestrial leeches can cause profound, life-threatening anaemia, but even more so do aquatic leeches. This type is acquired while bathing or drinking unfiltered water. They attach themselves to mucous membranes, having been described in sites like conjunctiva, nose, pharynx/larynx, trachea/bronchi, oesophagus, vagina, and rectum. Especially in the airways, they can cause even fatal bleeding or obstruction. Treatment consists of removal of the leech. Conclusion: in developing countries, even unusual causes like leech infestation have to be considered in the differential diagnosis of severe anaemia in children.