You can deduct medical costs you pay directly to medical service providers for another person according to the following rules:
- If you pay medical expenses for someone you do not claim as a
dependent on your income tax return, you can deduct those expenses if:
- He or she either lived with you for the entire year as a member of your household.
- He or she is related to you (as described in the section Who's a Relative).
- He or she was a U.S. citizen or legal resident, or was a resident of Canada or Mexico, for some part of the year.
- You provided over half of his or her support for the year.
Note that these rules are slightly less stringent than those for the dependency exemption. For example, it's possible that you can deduct medical expenses you paid for a parent in 2015, even though you can't claim the parent as a dependent because his or her gross income exceeded $4,000.
- If you paid a person's medical bill this year for an expense incurred last year, and that person was your dependent last year, you can deduct the expenses on this year's return even if he or she isn't your dependent this year. The key factor is that the person was your dependent when the medical services were provided.
- If you're divorced and pay medical expenses for your child, but don't claim him or her as a dependent because you are the non-custodial parent, you can still deduct those expenses. This assumes that you would qualify to take a dependency exemption for your child is you were the custodial parent.
- You can deduct medical expenses that you pay for your spouse. What most people don't know is that you can claim medical expenses for your spouse's medical treatments that occurred before you were married if you paid those bills after your marriage. The rule is that you must be married either at the time of the medical treatments, or at the time the bills are paid.
For a complete list of qualified medical expenses, see IRS Publication 502: Medical and Dental Expenses.