Young doctors in Barcelona stripped to their underwear in a bid to highlight claims they are on low salaries, don't get enough rest and have a lack of supervision.
It comes as hospitals in the region are struggling amid a surge in coronavirus cases.
The doctors said taking their clothes off was meant to symbolise a lack of protection they felt in doing their jobs.
Doctors take part in three to five years of residency at hospitals to specialise in a particular area of medicine.
But the pandemic has forced many to stop their specialisation to join the front line, assuming responsibilities many say they were unprepared for.