I drive my father-in-law to his dialysis appts. 6-7 times/month. I use my car & normally pay for gas. Can I itemize the mileage on taxes?

Other answer:

are you claiming him as a dependent? if not no
Yes, but you must keep honest and accurate records of these expenses in
a Log Book. Itemize, miles total for each trip, cost of gas per gallon, and the date.
Keep all receipts.You could also claim a small portion of your insurance and
wear and tear.
Not unless he's your dependent. If he is, you can deduct mileage only if you itemize, and only the total med/dental expenses over 10% of your AGI. That almost surely means no.
Pascal the Gambler:
Oh Wise One:
Yes, absolutely. You can deduct the mileage and any other travel expenses related to these trips.
Max Hoopla:
You can't but he can.
Bostonian In MO:
Is your F-I-L your dependent? If not, is the only reason that he's not your dependent is that his gross income was more than $4,050 in 2016 OR he filed a joint return with his spouse?

If he's your dependent or the only reason that he's not your dependent is the gross income test or joint return test are not met (you still must meet the support test) then you may deduct medical expenses that you paid on his behalf, including transportation costs. Medical transportation is deductible at 19 cents per mile. The usual 10% or 7.5% floors still apply.

If he does not meet the tests above, you cannot deduct any of his medical costs, including transportation costs.

Happy Gramps:
yes, BUT unless you have more deductions than the standard that IRS allows (which is not likely), then you can't itemize your return
yes you can. but if audited you will need receipts and a mileage log to verify your deduction.