I was using the waste disposal in the kitchen and when I went to the bathroom a few minutes later I had water coming up the drain.
The tub is now completely clogged. I have used drain and liquid plumber, but nothing is working.
I also noticed that if I use the sink in the bathroom, it is very slow draining and I have more water coming up into the bathtub.
Can this be fixed without calling a plumber? What has happened?

You have plugged the drain. Probably by using the disposal. Potato peelings ? They are notorious for clogging things up. In any case, you must unclog the drain. I suspect that since the sink is not backing up, the clog have moved away from the sink and is clogged at just before it empties to the street. If you are not handy, you will have to call a plumber or a drain man

Wally said it: snake your drain. It is clogged.

I was using the waste disposal in the kitchen and when I went to the bathroom a few minutes later I had water coming up the drain.
The tub is now completely clogged. I have used drain and liquid plumber, but nothing is working.
I also noticed that if I use the sink in the bathroom, it is very slow draining and I have more water coming up into the bathtub.
Can this be fixed without calling a plumber? What has happened?
It can be fixed without calling in a plumber if you're handy.
You have a blockage downstream from the bathroom.
Rent a sewer machine, (see image) and send it down the lavatory roof vent.
Put out enough cable to reach the base and 20 feet more. If you can locate the house cleanout you might open it up and observe the flow. Good luck, Tom

Thanks for the advice.
We rented an electric snake, but can not get past the blockage.
Any other suggestions, or is it time to call a plumber? Any idea how much $$ this will cost?

Use heart-shaped knife on tip of the cable. Stay on the clog for few minutes. Work cable back and forth. It will go.

Ok... I had lettuce and tomatoes in the bathtub... one of my ladies who live here had gone to the store for Drano... not happening. 1/2 bottle in the tub that was totally stopped up and 1/2 bottle in the kitchen that was draining into the tub followed by hot water... nothing. I did as instructed and took out the old end of the tub thingy with the lever for the stopper that has been long gone for 50yrs... 100 yr old house... and waala... lettuce all inside that thing. Then... cause I am not going into the garage in the dead of night to locate the auger I haven't seen in years... I tried an unwound wire hanger... perfect... hit the clog and cleared it... we are draining free and I am free of a big plumbing bill... awesome... I ran lots of hot water and it really is running just fine now. I will get somemore drain cleaner and run it through tomorrow just to be sure. I love the internet and this site ROCKS. Lindy in Houston Heights.

Hi lindy and Welcome to The Plumbing Page. At AskMeHelpDesk.com. You're responding to a 4 year old dead thread. Look in then upper left hand corner of the first post form the date in the first post before you post, Thanks,
GREAT! Thanks for your input and update. Tom