The safety, efficacy and complications of two techniques of endoscopic injection sclerotherapy were examined in 102 consecutive patients, using either a totally transparent over-tube or the free-hand technique. The choice of treatment was at random. There was a significantly higher control of variceal bleeding when the over-tube technique was used (100 per cent versus 77 per cent, P less than 0.05). The frequency of re-bleeding before the eradication of oesophageal varices was significantly less in the over-tube group than in the free-hand group (P less than 0.01), although all re-bleedings were well controlled with additional injections of 5 per cent ethanolamine oleate. There was no significant difference between the two techniques with regard to the frequency of endoscopic injection sclerotherapy for eradication of oesophageal varices. The over-tube technique is safer than the free-hand technique and takes less time to accomplish; at the initial session of treatment, time and bleeding during these techniques were 11.5 +/- 2.3 min (mean +/- s.d.) and 7.3 +/- 5.9 ml in the over-tube technique, and 20.4 +/- 4.1 min and 45.1 +/- 30.0 ml in the free-hand technique (P less than 0.001, in both time and bleeding).