Dependence on the help provided by other people increases the risk of a person being inappropriately treated. Our objective was to investigate inappropriate treatment and its context in the care of people with dementia. Some 85 clients across eight care units providing dementia care were observed by means of a structured Dementia Care Mapping method (DCM). Of the 17 DCM categories for inappropriate treatment, withholding, invalidation, and objectification were the categories coded most frequently. Inappropriate treatment episodes were mostly associated with eating and situations in which a client had a need or request. Most episodes occurred accidentally. The results show that nurses involved in dementia care need more knowledge of how illnesses causing dementia change the way the affected person experiences reality, and of the ethical aspects of their work.