Two low-income Illinois women have filed a lawsuit claiming a new definition of charity care for tax-exempt hospitals violates the state constitution.

The lawsuit was filed Tuesday in Cook County Circuit Court in Chicago. Plaintiffs Aracely Sebastian and Maria Maldonado want the court to declare a law passed last year unconstitutional.

Their attorney, Caroline Chapman, says changes made to the state revenue code unconstitutionally broadened the definition of what hospitals need to do to qualify for lucrative tax exemptions.

The Illinois Department of Revenue and its director are named as defendants in the lawsuit. Department spokeswoman Susan Hofer says the agency doesn't comment on pending litigation.

Illinois Hospital Association spokesman Danny Chun says last year's law was "carefully drafted" to keep the constitution in mind.