NHS watchdog Healthcare Improvement Scotland (HIS) revealed its workers took action after discovering pensioners at Wishaw General Hospital, in Lanarkshire, had been going without food.
The incidents came as inspectors returned to the hospital after being concerned about their initial findings during a routine probe.
Details emerged in an HIS report published yesterday which also described a patient complaining staff had borrowed her walking frame for another pensioner.
The team said they twice heard patients being called the wrong name and also heard staff using terms associated with babies in relation to the elderly for example shouting "she's feeding" down the ward.
According to the document, one relative told them: "On one visit we were appalled to find [my father] sat on his bed naked in his own urine with no screen around him and this was during visiting hours."
Areas where Wishaw General was serving elderly patients well were also noted in the report, such as involvement of carers when discharging pensioners.
Susan Brimelow, chief inspector for HIS, said: "We noted areas where NHS Lanarkshire is performing well. We saw some good examples of staff using personal care plans to improve the experience and provide better outcomes for patients.
"However, we also found a number of areas where improvement is required, in particular we had significant concerns about the needs of patients not being met in one ward.
"As a result we have conducted a follow-inspection which assured us progress is being made to address the issues we identified."
Inspections into the care of the elderly were organised in Scotland after concerns were raised about how their needs were being met.
Doctor Richard Simpson, Labour's health spokesman, said: "We are seeing more and more shocking failures in elderly care and the experience of some of the patients at Wishaw highlighted in this report falls way below what we would expect of a 21st-century hospital. The SNP Government has made deep cuts to the hospital staffing levels and the dignity of our elderly is being compromised as a result."
NHS Lanarkshire said action was being taken. Rosemary Lyness, director of Nursing, Midwifery and Allied Health Professions, said: "We are continually improving the level of care we provide to older people and the report includes valuable feedback to help us achieve this.
"A range of actions to benefit patients are already being taken forward through a detailed plan that addresses areas for improvement found by the inspectors."
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