The rights group said Bahraini forces took over the country's largest public hospital March 16. Patients injured by rubber bullets and live ammunition during clashes with government forces are the target of the country's military.
"There is absolutely no justification for arresting someone solely because the person might have been wounded in a protest-related incident," said Joe Stork, Middle East deputy director at Human Rights Watch, in a statement.
"It is against every tenet of humanity to deprive patients of critical and sometimes life-saving medical treatment, causing them grave suffering and perhaps irreparable harm."
The government in response to similar complaints last week said some of the country's medical facilities were "overrun by political and sectarian activity," reports CNN International.
U.N. High Commissioner for Human Rights Navi Pillay said she was deeply alarmed by the escalation of violence in the country, describing the March 16 seizure as "shocking and illegal conduct."
Human Rights Watch added that security forces transferred many patients to other medical facilities, often against the advice of hospital staff.