If you are talking about stains on a ceiling that you want to cover I have had good luck with the oil kilz in a spray can. It is a bit salty and I never get the full can used because it clogs the spray tip.
I believe they have a urethane version as well that might do better.
They will both smell for a bit until cured.
If it is just a water stain from a leak that was fixed you can use the latex based sealers. They do not smell as bad. But they do not seal as well either.
After you seal the spot(s) and they have dried completely you will need to paint the area or the entire ceiling as the pigments in the spray probably won't match what is up there.
Maybe this is what you were asking. Maybe I just wasted your time.
Either way I hope it helped a little. --107.147.xx.xxx