Some kind of cancer is what I've always thought. With cancer, your appearance doesn't necessarily.

With diabetes, she'd have been a lot worse off and the symptons would have been a lot more obvious.

that sad that she had to die in pain and alone.

Wolf36, she didn't die alone... Her sons were with her. (Either that or in that scene she fell asleep.)

What I don't get is that they have the medical technology to make something as brain-twisting as automail, but they couldn't treat whatever she had... YOU THINK THEY'D BE ABLE TO CURE THE COMMEN COLD WITH THAT TECH LEVEL!

I'm not 100% sure of this but I think that it was the same disease that their teacher had as well...They did not go into details like they did with teacher because Trisha's character although sparked the series was not very important