“…The most promising aspect of photosensitization in medicine seems to be cancer therapy. It is well documented that a few dyes, among them haematoporphyrin, are preferentially taken up and retained by malignant tumours in animals as well as in humans (Auler & Banzer, 1942;Figge et al, 1]948; Lipson et al, 1961;Gregorie et al, 1968;Winkelman & Rasmussen-Taxdal, 1969 (Kelly et al, 1975;Granelli et al, 1975;Dougherty et al, 1976). Particularly promising is the recent work of Dougherty et al (1978) in which the authors document complete or partial remission of 111/113 cutaneous or subcutaneous malignant tumours of different types in humans.…”