The workers, including midwives, paramedics and radiographers, are suspending all non-urgent care for four hours. The strike is related to health secretary Jeremy Hunt's decision not to award a blanket 1% pay increase to NHS staff in April of this year, ignoring the advice of the Pay Review Body (PRB).
It follows a widespread day of action on 13 October. As then, the unions involved represent around 400,000 NHS staff, although it is not yet clear how many are involved in the strike.
As well as the strike, two further unions, the British Dietic Association and the Hospital Consultants and Specialists Association, will this week take industrial action short of striking. This involves refusing to work more than contracted hours between 25 November and 30 November.
A spokesman for the department of health claimed proposals for an increase of at least 1% this year and 2015 have been put on the table, but rejected by the unions.
"We have taken tough decisions to increase the NHS budget, but we can't afford a consolidated pay rise in addition to increments without risking 10,000 frontline jobs," he said.
Unison general-secretary Dade Prentis warned that "anger is spreading" among NHS staff over the inability to reach a deal on pay.
"The strength of feeling is far from fading and the dispute far from going away," he said. “All the government has done so far is threaten workers with job cuts.
"If the secretary of state seriously thinks staff are the NHS’s best asset then he needs to treat them fairly. We are only asking for decent pay for the hard working people the government say they care so much about."