Constitution of the State of Ohio Art. XII, § 3

(A) The taxation of decedents' estates or of the right to receive or succeed to such estates, and the rates of such taxation may be uniform or may be graduated based on the value of the estate, inheritance, or succession.  Such tax may also be levied at different rates upon collateral and direct inheritances, and a portion of each estate may be exempt from such taxation as provided by law.

(B) The taxation of incomes, and the rates of such taxation may be either uniform or graduated, and may be applied to such incomes and with such exemptions as may be provided by law.

(C) Excise and franchise taxes and for the imposition of taxes upon the production of coal, oil, gas, and other minerals;  except that no excise tax shall be levied or collected upon the sale or purchase of food for human consumption off the premises where sold.