A man arrested on suspicion of murder has been released by police pending further enquiries.
Officers arrested the 26-year-old man, from Preston, after being called to a flat in Ashton, following reports of a woman being found unresponsive at the home.
Paramedics took the 24-year-old to Royal Preston Hospital where she was pronounced dead on arrival.
A Home Office post mortem has so far proved inconclusive, but the death is not deemed suspicious.
Lancashire Police said this morning that the man has now been released without charge after being arrested on suspicion of murder.
However, he has been bailed pending further enquiries in relation to allegedly being concerned in the supply of a Class A drug, cocaine. He has been bailed until June 30.
Paramedics were called to the flat on Heywood Road, Ashton, at around 5.25am on Saturday.
Further toxicology tests will now be undertaken to try to establish the cause of death.
A file will be passed to the coroner.