Receiving "public assistance" adversely affects your green card application process.  Therefore, it is important to know which benefits are considered or not considered "public assistance."  One of the most common questions pertains to Medicaid.

About Medicaid, USCIS has explained as follows:
--- If Medicaid is used to support aliens who reside in an institution for long-term care (such as a nursing home or mental health institution), it may be considered as an adverse factor.
--- However, if Medicaid is used for other purposes (such as immunizations, testing and treatment of communicable diseases, health clinics, short-term rehabilitation services, prenatal care, emergency medical services, etc.), it does not affect the green card process.

For details, please see the following link: http://www.uscis.gov/portal/site/uscis/menuitem.5af9bb95919f35e66f614176543f6d1a/?vgnextoid=775d23cbea6bf210VgnVCM100000082ca60aRCRD&vgnextchannel=8a2f6d26d17df110VgnVCM1000004718190aRCRD