How can I unclog my toilet and bathtub?
Also asked, why is my toilet water going into my bathtub?
When you flush the toilet, water backs up into or comes up in the tub or shower. When your sewer line is clogged, the water can't go down the drain. When you run water in the bathroom sink, the toilet bubbles and gurgles. The bubbling is due to air trapped in the plumbing system.
Just so, how do you fix a toilet back up into the shower?
You may want to get a second standard plunger and have an assistant seal off the drain in the shower to increase the thrust action of the plunger. Plunge the toilet up and down several times and then quickly break the seal by pulling the plunger up. You may need to do this several times to force the blockage through.
Drano uses caustic or oxidizing chemicals (like lye) to dissolve whatever is clogging a drain. The chemical reaction between the clog and Drano creates heat. Now, Drano does not clear a clog instantly. It's going to sit in the toilet (or farther down the pipes, depending where the clog is) until the clog dissolves.