Caregivers play a determining role in choosing treatments for persons with Alzheimer's disease. The objective of this study was to examine caregivers' willingness to have persons with Alzheimer's disease continue taking cholinesterase inhibitors in the event that any 1 of 11 adverse effects was to occur. Data were gathered via postal questionnaire from 375 caregivers in Montreal. Sixty-four per cent of caregivers responded (n = 201), and most ([greater than or equal]59%) were willing to continue treatment if persons with Alzheimer's disease suffered from weight loss or loss of appetite. However, most ([greater than or equal]53%) were not willing to continue treatment in the event of headache, dizziness, nausea, diarrhea, vomiting, drop in blood pressure, insomnia, muscle cramps, or stomach bleeding. The use of cholinesterase inhibitors by persons with Alzheimer's disease was positively associated with caregivers' willingness to accept greater numbers of adverse effects (adjusted relative risk = 1.97; 95% CI = 1.11 to 3.61). Caregivers appear to make a risk-benefit assessment when they decide whether or not care-recipients should continue pharmacotherapy in the event of adverse effects.