Elijah Blue Allman overdosed in Southern California this weekend … TMZ has learned.

Sources familiar with the situation tell TMZ … the son of Cher and the late Gregg Allman was rushed to the hospital in Joshua Tree, CA after overdosing earlier Saturday morning. We don’t know what drugs he was using.

We’re told he’s still in the hospital and receiving the best care possible … and, he’s very lucky to have survived.

Elijah’s detailed his struggle with substance abuse issues in the past … revealing in a 2014 interview that he started taking drugs when he was just 11 years old.

During the interview Elijah said he had several close calls with overdosing … saying, “I did have some close calls and some moments of really feeling at the edge of mortality … I always kind of kept it a little bit safe but you never can do that.”