Doctor Marsh is a Horde Alchemy trainer located in The Apothecarium in Undercity.
He is in the Apothecarium. As you face the entrance to the Royal Quarter, there's an open area to your left. He is down there behind the counter.
Doctor Marsh trains Alchemy from skill 50 to 150. Below 50 go to Doctor Martin Felben in Undercity. Past 150 go to Doctor Herbert Halsey in Undercity.
Undercity
Doctor Marsh
