Donations are limited on how much you can deduct. In general, for Qualified Donations, the basic rule is that you can deduct up to 60% of the amount of your adjusted gross income.
Some donations however have a lower/higher cap percentage rate, and some do not qualify to be deductible at all.
Make sure that your donations qualify to be deductible.
Click on the link below for more information on which donations qualify and for the caps of each type.
Charitable Contributions