One example of this that I have heard about has been thalidomide. Thalidomide was used to treat nausea and morning sickness in pregnant women in the 1950’s. Previous studies in mice showed that thalidomide was not a risk in mice, but it is in humans. It caused limb deformities/absence and phocomelia in the unborn babies and was withdrawn from the market in 1961. The mechanism of action was and is still not well understood. In this case, animal models were not an ideal representation of possible risks. Furthermore, thalidomide is used in healthy, non-pregnant patients to treat a variety of conditions such as erythema nodosum, leprosy, actinic prurigo, cancer, and HIV. It was unknown that it could have a negative effect on embryonic development at that time and previous data could not indicate the possible risk. Oftentimes, with these risks and outcomes, there are lawsuits that allow the patient to have some kind of compensation for their loss.