There are a number of methods that can be used to get red wine stains out of a carpet including salt, oxi products, liquid dish detergent or a hydrogen peroxide mix. All methods will work differently depending on how long the stain has been there as well as the color and the makeup of the fabric fibers in the carpet.
If the red wine stain is new, then salt should be added immediately. Salt absorbs products and will absorb the red wine. Once this process is complete, the salt can be removed with a vacuum and cleaning solutions can be applied.
One useful cleaning solution is oxi products. Oxi products work well on both old and new stains. The oxi product should be left on the stain from 2 to 10 hours so be sure to block off the area to keep pets or young children from disrupting the process.
The hydrogen peroxide mix should only be used as a last resort because it can alter the color of the carpet in some cases. Mix a solution that is 1/3 dish detergent and 2/3 hydrogen peroxide. Gently dab it on to the stain and back off again.