This study was conducted in 47 patients with biopsy-proven cancer of the head or neck. These patients each had an intra-arterial infusion tube inserted retrogradely. Positioning in the infusion tubes had been determined by staining of the mucocutaneous area of the malignant lesion under observation with injection of blue dye. Digital subtraction angiography (DSA) was performed from the infusion tube. DSA demonstrated that infusion tubes were in the correct position in 26 patients (55%), and in an incorrect position in 21 patients (45%). The infusion tubes of all patients with cancer of the maxillary sinus were in the correct position. However, the majority (54%) of infusion tubes in patients with cancer of the tongue were in an incorrect position. Observation of arterial flow from the infusion tube using DSA should be made in all patients with head or neck cancer in order to avoid the potential complications of intra-arterial chemotherapy.