New quinolones have obtained a definite position in the treatment of certain sexually transmitted diseases, urinary tract infections, prostatitis, gastrointestinal infections, nosocomially acquired pulmonary infections with resistant organisms, pseudomonas infections in cystic fibrosis, and osteomyelitis. The role of the new quinolones in upper respiratory tract infections, acute or chronic bronchitis and community acquired pneumonia is far less established. Their role in selective decontamination of the gastrointestinal tract in neutropenic patients is under investigation. Future modifications may increase their usefulness for treatment of mycobacterial infections, chlamydial infections, and mycoplasma and ureaplasma infections. The structural relationship of the new quinolones with antimalarial drugs may open new perspectives for the treatment of falciparum malaria.