The U.S. comic was checked into an unnamed medical facility over the weekend (02Jan10), but his spokesperson refused to give any details of the reasons for the admittance.
Stern has hinted that troubled Lange - who was ordered to attend an intoxicated driver resource program last year (09) after driving under the influence of drugs - could be struggling with his demons once again.
But he urges fans to remember the comic's talents before judging him.
Stern tells E! Online, "We all have our demons. Artie has given this show tremendous moments of great comedy. He's a tremendous contributor. He is a good man. Don't forget how great he is."
No further updates on Lange's condition have been released since Saturday's initial statement.