Newcastle's only goal came from the penalty spot, with Joey Barton converting after Obafemi Martins fell in the box.
It was strange to see Alan Smith wear the skipper's armband, and I'm sure he won't forget his first game as toon captain.
Orient's opener came after just three minutes when Jimmy Smith headed past Tim Krul.
Beye gave away a needless penalty in the 22nd minute when, under pressure from Adrian Patulea, handled in the box. Thornton converting from the spot to make it 2-0.
Orient fans started chanting 'you're not famous any more' when the 1,500 Toon fans shouted Alan Shearer's name.
Referee Jarnail Singh awarded Newcastle a questionable penalty when Martins fell under a challenge from Tamika Mkandawire
Barton coolly converted the spot kick fto make it 2-1.
Changes were made in the second half, with Geremi, Xisco, Fraser Forster and Andy Carroll all coming on.
Scott McGleish beat Forster a little too easily for many fans' liking, and he was soon picking the ball out of the back of the net again soon after.
Seconds after the restart, Mkandawire added a fourth from a corner as the visitors' performance fell apart alarmingly.
Smith was replaced by Danny Guthrie on the hour mark, and the skipper's armband was passed to Taylor, then to Kevin Nolan after Taylor left the field.
Ryan Jarvis who made it 5-1 with eight minutes left, and Harry Baker smashed in a sixth before the final whistle.
NEWCASTLE UNITED: Krul (Forster, 46); Beye (Tozer, 80), S Taylor (Lough, 80), Coloccini (Geremi, 46), Enrique (Kadar, 73); Gutierrez, Barton (Xisco, 46), Smith (Guthrie, 60), Duff (LuaLua, 73); Nolan; Martins (Carroll, 46). Subs not used: Donaldson, Ngo Baheng.