"Sales have been halted in all the pharmacies in the 18 countries of the European Union where it is distributed," a company spokesman told AFP.
Sanofi-Aventis said the European Medicines Agency (EMEA) had warned that patients taking the drug ran almost double the normal risk of psychiatric problems.
"The risks of taking Acomplia are now greater than the benefits that the drug can bring the patient according to its current guidelines," the company said, citing the EMEA.
Europe has allowed sales of Acomplia since 2006, but it has not been authorised in the United States where authorities believe it encourages suicidal thoughts, even in patients with no history of depression.
The company said it had not ruled out withdrawing the drug in the 14 non-EU countries where it is sold. It said users of the drug should consult a doctor or pharmacist.