The incident on Friday, 2 January resulted in one man in his 30s suffering serious injuries to his ear. The man has since been discharged from hospital.
A woman in her 40s and a man in his 70s also suffered minor injuries and were treated at the scene.
Detective chief inspector Mike Sharples of GMP's Bolton district said: ‘We understand that an incident of this nature has caused concern for members of the public who were in hospital at the time, staff and the wider community.
‘Officers are continuing to engage with staff and patients at the hospital to conduct a thorough investigation into the circumstances of the incident.'
The suspect was charged with two counts of Section 47 assault, Section 18 assault, police assault and racially aggravated public order.
He was taken into custody and has been detained under Section 136 of the Mental Health Act.
Bolton NHS Foundation Trust has been approached for comment.
