The authors present an account on the possible use of photodynamic treatment of malignities of the digestive tract. Although in the Czech Republic the development of photosensitizing substances is successful, this interesting and perspective method is not used in our practice. The paper contains an explanation of theoreti- cal aspects and practical possibilities of this treatment and informs on the development of phthalocyanin derivate as a perspective preparation of the second generation in the Research Institute for Organic Synthe- ses – Pardubice-Rybitví.

        Key words: photodynamic therapy – laser – porphyrins – phthalocyanine derivate