Abstract: The invention relates to the use of N-substituted indole-3-glyoxylamides of the general formula I as antitumor agents and to a pharmaceutical composition having antitumor action, characterized in that it contains at least one of the compounds of the general formula 1, if appropriate also in the form of the physiologically tolerable acid addition salts or N-oxides. Furthermore, the invention also includes antitumor agents comprising as active compound one or more N-substituted indole-3-glyoxylamides according to the general formula 1 and, if appropriate, their physiologically tolerable acid addition salts and, if possible, N-oxides and a pharmaceutically utilizable carrier and/or diluent or auxiliary substance in the form of tablets, coated tablets, capsules, solutions for infusion or ampoules, suppositories, patches, powder preparations which can be employed by inhalation, suspensions, creams and ointments.