Other lawyers said there are many plaintiffs with lung disease that they say was caused by the diet drug.
The researchers did not know when each woman got the diet drug or a placebo.
Doctors then made the connection to the diet drugs, although they have not clearly shown cause and effect.
Learn the truth about diet drugs and what they can really deliver.
The unit has also benefited as people have quit taking diet drugs because of safety concerns.
But when it comes to a culturally sensitive area like weight, the widespread use of diet drugs is unlikely to stop.
"We are not a medical organization, and the decision to take diet drugs should be made with the individual and his or her physician."
Whether that pressure played any role in the decision to approve the new diet drug despite the questions raised about it is uncertain.
Experts explain the benefits and side effects of the over-the-counter diet drug.
Across the country, doctors say they have seen a great deal of interest in the diet drugs from patients who have had trouble losing weight.