Bialybah, this may be a better topic for the houseplant forum, but if we are to try to address it here (of for that matter, if the Houseplants Forum people try to address it there), we'll need LOTS more information.

When you say that the roots look bad, how do you know? Have you repotted recently? How's your soil drainage and how often do you water? How large is your pot and how much water do you give the plant? Do you allow the potting media to dry out in between waterings? If so, how do you know what the moisture level is like down at lower levels in the pot?

Is this a new plant or one that you've had for a while? Is the problem something that has gotten worse over time or something that seems to have happened over a short period? Can you give us details about what you've seen and when you've seen it? Can you give details of any changes you've made or tried (replanting, changing watering procedures, changing locations or lighting, etc, etc)?

If I had to guess, I'd guess your plant's problem is related to watering and soil moisture levels, but without more information, an accurate diagnosis is impossible.