There are many types of chemical strippers to use for a hardwood floor. The type of stripper you use should depend on what you want to accomplish and how you want to accomplish it. If you are stripping several layers of stain from a hardwood floor, a strong solvent based stripper is best. But for lighter jobs, citrus and soy strippers are a great option.
The best chemical strippers for a hardwood floors are solvent based. That means they dissolve the paint material using powerful chemicals. These strippers are basically the same thing as paint strippers, but they have properties that allow them to be used on hardwood floors. Check the labels of all strippers you encounter to see what they are recommended for. Peel Away 7 is one of the best on the market; it is strong, relatively light in terms of fumes and comes in an easy-to-apply paste so it won't spill. It also works well on stains and paint.
A natural stripper is one that uses a lemon citrus or soy base as the active ingredient. Both citrus and soy can remove paint from hardwood floor. They are great for removing a light stain on a small area of hardwood, especially if you want to reduce the damage that might occur to the wood. These products also will not damage carpet or your walls as easily as a stronger solvent-based stripper will. Still you should take precautions and tape off any areas you don't want damaged before using any product.
Paint or Stain
There is a big difference between paint and stain, but a chemical stripper can be used to remove both, you just need to find the right ones for each application. A solvent is easy to use on small spaces and furniture because it can be spread easily. Peel Away 7 will strip both as well. With Peel Away, you can apply to the surface and scrape it away with a plastic scraper. With a solvent, you will have to apply the product, and then scrub it away with a tough bristle brush. This can be messy, so use plenty of plastic and tape to protect surrounding wood and trim. It will also damage hardwood and scratch the surface.