There has been a 15-fold increase in prosecutions of people who physically assault NHS staff, new figures show.
The RCN claims a tiny proportion of assaults are reported to police
Department of Health figures showed there had been 759 prosecutions in 2004-5, compared with 51 in 2002-3.
The NHS Security Management Service has since 2003 taken steps on the problem, such as setting up a national reporting system to track repeat offenders.
Health Secretary Patricia Hewitt said the figures demonstrated "tough action" would be taken over assaults on staff.
She added: "Although I am pleased with this increase, it also illustrates the extent of the problem.
"Working with the NHS Security Management Service, I am determined to reduce the number of violent incidents occurring in the NHS.
"NHS staff should not have to tolerate abuse."
Security Management Service (SMS) chief executive Jim Gee said: "The vast majority of the public find violence against NHS staff to be completely unacceptable.
"The small but anti-social minority who carry out such attacks should understand that we shall take the toughest possible action against them."
The SMS' new measures include establishing a Legal Protection Unit to ensure prosecutions are pursued, and a network of Local Security Management Specialists to investigate alongside police.
It is also negotiating an agreement with the Association of Chief Police Officers on investigating and prosecuting assaults.
High-profile prosecutions include, in June this year, a life sentence for a man found guilty of stabbing a nurse at York Hospital in 2004 - the nurse suffered minor lacerations.
Also in June, the NHS SMS successfully applied for an anti-social behaviour order (Asbo) against a man who had verbally and physically assaulted NHS workers 47 times in five months.
The Abso banned Norman Hutchins, 53, of York, from any NHS buildings without lawful excuse or prior arrangement.
'More to do'
The Royal College of Nursing (RCN) responded to the figures by saying that in 2002-3 just 5% of 116,000 violent or verbal assaults were reported to police, and just 2% prosecuted.
"There has historically been a very small number of prosecutions and these [new] figures come from a very low starting base," said RCN England Director Tom Sandford.
He added: "We should be doing everything we can to recruit and retain nurses - nurses who feel secure and valued can then get on with the job of caring for patients without worrying about being attacked.
"There is still a long way to go and much more that can be done.
"The political will is there from the government and politicians across all parties to really tackle this problem, and we will be pressuring the government to maintain this momentum."