It has been much easier to obtain original data on adverse drug reactions (ADR) of quinolones from the pharmaceutical industry than it was two years ago. This is to be welcomed and, as anticipated, the new data continue to suggest that the new 4-quinolones have an ADR profile which is very similar to that of other antimicrobials. Visual disturbance is not a prominent feature, in contrast to the ADR profile of nalidixic acid. Better definition of quinolone ADRs requires prospective study, and the results of a newly completed prescription event monitoring study are awaited with interest. The potential use of computerised databases and record linkage is examined, but at present the number of quinolone prescriptions is too small to assess documentation of serious but rare events such as convulsions. Physicians need to be aware of the limitations of current data on suspected ADRs. Further investment in computerised databases is required to satisfy the requirements for attributing causality of an event to a drug.