Junior doctors should consider their "professional responsibilities" before their next strike, England's chief medical officer has said.
The first full walkout in the history of the NHS by junior doctors is planned for the end of the month, when they will withdraw all labour and provide no emergency cover.
It is the latest strike in the long-running - and increasingly bitter - dispute with the government over a new contract.
Professor Dame Sally Davies said the move was a "drastic step" that would "inevitably lead to patients suffering".
Dame Sally did admit, however, that she understood the "anger and frustration" felt by many in the profession.
Junior doctors will stage their next strike - the full walkout - on April 26 and 27.