Parents of three have pleaded not guilty to the charges, though they both admitted to being heroin users, BBC.
A young couple in the US state of Washington gave children drugs to "make them go to sleep".
Ashlee Hutt and Mac Leroy McIver have been charged with child endangerment on Monday after rat droppings, drug needles and heroin were found in their house.
Three children aged six, four and two were were removed from the home last November.
The six-year-old told investigators the couple gave him "feel good medicine" which he described "as white powder which was mixed with water" and injected with needles, according to court documents.
He said after they were injected the three children would go to sleep.
Pierce County Sheriff's Department spokesman Ed Troyer told The Washington Post: "The kids lived in deplorable conditions. It wasn't a good living situation even without the issue of heroin."
Two of the children tested positive for the drug, and puncture marks and bruising, consistent with needle injections were also found on the children's bodies, according to reports.