[throwaway672000]

Thalidomide might be what you're thinking of. Didn't realise until now that it wasn't approved in the US until the risks were well known. But in the UK at least "thalidomide was (supposed to be) safe too" is an easy argument you'll hear fairly often.

>... a subsidiary of Distillers Co. Ltd (now part of Diageo plc), marketed thalidomide throughout the UK, Australia and New Zealand, under the brand name Distaval, as a remedy for morning sickness. Their advertisement claimed that "Distaval can be given with complete safety to pregnant women and nursing mothers without adverse effect on mother or child ... Outstandingly safe Distaval has been prescribed for nearly three years in this country."

>Experts estimate that thalidomide led to the death of approximately 2,000 children and serious birth defects in more than 10,000 children, about 5,000 of them in West Germany