Is home health aide costs tax deductible? wife cannot dress, toilet, bathe, or transfer without much assistance.

• If the expenses are for medical needs, it is possible they could be used as a Medical Expense.  However, Medical Expenses are severely limited to the amount OVER 10% of your income (7.5% if age 65 or older until December 31st 2016, then it reverts to 10% for everybody).
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  However, only expenses for actual medical care can be deducted as medical expenses.  That does not include non-medical services such as preparing their meals or keeping them company.

If she is physically unable to care for herself, and you pay for care so that you can work, the expenses are eligible for the Child and Dependent Care Credit.  See here for the rules. https://www.irs.gov/pub/irs-pdf/p503.pdf

If you're retired or don't have earned income, then the medical expense deduction is the only option.