Europe has introduced a database to make the public aware of suspected side effects in medicines.
The online library, on http:www.adrreports.eu/, so far contains information relating to around 650 drugs, the London-based European Medicines Agency (EMA) said.
"Today's launch... highlights the importance of side-effects reporting and pharmacovigilance in safeguarding public health within the European Union," it said.
The reports come directly from the European Union's medicines safety database, called EudraVigilance.
The information comes from reports of adverse reactions submitted by patients and doctors to national regulatory authorities, as well as by pharmaceutical companies, which are legally required to do this to gain a licence to sell a drug in the EU.
EMA stressed that the data relate to suspected side effects.
"Suspected side effects may not be related to or caused by the medicine, and as a result, the published information cannot be used to determine the likelihood of experiencing a side effect or as an indication that a medicine is harmful," it cautioned.
The reports are being published first in English but should be rolled out in the EU's 22 other official languages in the coming weeks.