Medical marijuana had been baked into a cookie, according to police.
The 3-year-old was rushed to the hospital Saturday after family members could not wake the child.
More details in the case revealed the THC oil was baked into cookies stored in a refrigerator in the garage, The Press-Enterprise reported.
The cookies were baked by the grandmother, a cancer patient who had a prescripton for medical marijuana, Murrieta police Sgt. Phil Gomez told the newspaper.
Police were awaiting toxicology reports to determine whether any child endangerment charges would be filed, the newspaper reported.