Aid workers at charity Medecins Sans Frontieres used local prostitutes while working in Africa, whistleblowers have told the Victoria Derbyshire programme.
Female former employees said the behaviour was widespread.
One said a senior colleague said it was possible to barter medication in exchange for sex.
The women spoke anonymously for fear of being blacklisted by foreign aid agencies, among which there can be a large crossover of staff.
“I felt that, with some of the older guys, there was definitely an abuse of power. They’d been there for a long time and took advantage of their exalted status as a Western aid worker,” she said.
“There’s definitely a feeling that certain predatory men were seen as too big to fail.
The Victoria Derbyshire programme has spoken to eight women in total who used to work at MSF in various European offices and field offices in Africa.
The charity’s culture was described as “toxic”.