Jurors took only one hour to find Carlotta Brett-Pierce guilty of murder.
An autopsy later determined high amounts of the allergy medication Claritin and Benadryl in her system.
Brett-Pierce was later charged with the girl's murder.
The victim's grandmother Loretta Brett, was charged also charged in connection to the murder as well as two ACS workers who did not prevent the death.
Brett-Pierce faces 25 years to life in prison when she is sentenced June 6.