New quinolones are notable for their high level of antibacterial activity, especially against gram-negative pathogens, and also for their specific pharmacokinetics involving good bioavailability after oral administration, high distribution volumes and a long elimination time. In view of these properties the more recent quinolones can be regarded as on a par with the modern beta-lactam antibiotics and aminoglycosides, which, especially through the possibility of oral administration in infections with problem organisms such as Pseudomonas aeruginosa or Serratia, represent a therapeutic advance. To maintain this advance the indications for therapy must be approached in a restrictive and critical spirit; the newer quinolones are only rarely the drugs of choice and should be held in reserve for complicated infections of the respiratory tract, the intestinal tract, the urinary tract and the bones. In regard to tolerance, particular consideration should be given to the specific CNS intolerance reaction.