Is ulcerative colitis deadly?

There is a slight increase in the chance of untreated UC becoming cancer. There are many new medications available now, and many people live to old age with it. The sad news is that there is no real CURE except surgery, which comes with it's own difficulties .There can be periods of remission, if you are lucky.

Question has been answered

You're on the internet. I assume you can do a basic search on the term of the disease?

I would hope you are under the care of a gastroenterologist

its nothing to mess with. Go to an internist for treatment.