Fifty years of experience with aminoglycoside antibiotics has confirme
d their usefulness in many infections with Gram-negative bacteria. The
ototoxic action has been investigated clinically in patients and in n
umerous animal studies. The increased knowledge about molecular struct
ure, pharmacology and pharmacokinetics as well as information of the s
ite of action in the labyrinth has resulted in reduced risks for sever
e toxic damage in kidneys and in the ear. Nevertheless, a number of ca
ses of severe hearing loss and a few cases of deafness still occur eve
ry year. Further studies on modified molecular structure as well as si
te of action at the molecular level and ways of avoiding toxicity will
make this group of antibiotics still more useful.