TMZ.com said the jury unanimously concluded Daniel died from "non-dependent drug use." It recommended no criminal charges be filed in the case, the report said.
Daniel Smith died at the age of 20 in September 2006, while he was visiting his mother in a hospital in the Bahamas.
Anna Nicole Smith had just given birth to Dannielynn Hope, Daniel's half-sister.
Anna Nicole Smith also died of an accidental drug overdose in February 2007.