Continuous intravenous colistin (2,000,000 units per 24 h) was administered in a 41-y-old patient with Acinetobacter baumannii bacteraemia, which led to the cure of the infection. The isolated microorganism was a multi-resistant strain (it was sensitive only to colistin). In addition, the patient had developed allergic reactions to previously administered antimicrobial agents of several classes during his hospitalization. Continuous intravenous infusion of colistin proved to be a salvage regimen, which led to cure of a bacteraemia due to a multi-resistant isolate, without showing any allergic cross-reactivity with other antibiotics.