Painting - Foul smelling latex paint

I have a 5 gallon plastic container of interior latex, flat paint. The paint has a foul smell. The container was previously opened, but still has most of the original 5 gallons remaining. Is there any additive or procedure to remove the smell and restore the paint to its original consistency. Thanks.

I doubt you will be lucky enough for any of these ideas to work but no harm to try.I have attempted many different ways to overcome soured paint but success is about 50%.I have boiled popourri(about a quart)and stirred into paint of course using your favorite.Very small amount of cheap perfume,a quart of lemon ammonia.This may sound odd but all of these have worked at one time or another.If the odor is not to bad opening all windows all day will help and once dry is not a problem.

A friend told me recently that a teaspoon of vanilla takes away paint smell... has anyone else heard of this?

Vanilla in paint does work. I use it when ever I paint. It's great during painting and afterwards while it's drying. No foul smell of paint.

I have also used vanilla extract in paint, and in most cases it works beautifully. The room will smell like you are baking cookies. However, it does not work in all paints. It will not work when mixed with some of the really bad smelling primer/sealer/stain-killers.