Quick tip, don't believe most of the stuff on the internet about how to get out stains. They usually tell you a good way to lock in a stain. I Google How to get Kool-aid stains out of carpet. Most sites told me to use club soda, this might lighten the stain but it will make it even harder or impossible to get it out completely. If you have newer high quality carpet or you have had good protector applied you may be able to just blot up the stain.
There are new types of carpets out there that will resist or not allow Acid dye stains 'Kool-Aid' to penetrate your carpet. One good example of this would be polyester. These carpets look good when they first go in but don't seem to hold up as well as good old nylon carpet. Every year they come out with some new trademarked carpet that is supposed to be better than nylon and can't be stained what so ever. I have not found one yet that I think is worth installing.
I recommend a good 5th generation nylon or even wool if you have more money than you know what to do with. Wool is by far the best longest lasting carpet fiber available but it is expensive. The problem with both wool and nylon is that they both except color very well. This is good in manufacturing but not good when you spill wine. A good first line of defense is carpet protector. Carpet protector can save you from many stains if you act fast. When you have an accident blot up the stain fast, you only have a short window before it starts to penetrate the protector. Below I have put together a sure fire way to remove most acid dye stains from nylon or wool.
Get yourself a good professional acid dye remover from the internet or a carpet cleaning supply store. I prefer the 2 part to the 1 part, but many of my technicians say that the one part works just as well. Here are some brand names Red One, Pro's Choice Red Relief, Red Zone Ready, Red Zone Stain Remover, Prochem Red Rescue. Inter Link Supply is a good carpet cleaning supply store. Online the cheapest place I have found theses chemicals is Steam Brite. The bottle will have instruction on what to do. I will be just going over the basic steps and give you some tips. Make sure to read the label for whatever spotter you purchase.
Apply the spotter of your choice according to the label. Some come with trigger sprayers some you have to mix. I like to apply the spotter with an over sized medical syringe without the needle. It allows me to precisely apply spotter exactly where it is needed.
Sometimes the spotter works immediately, but more often you need to apply heat to accelerate the chemical. You can use a blower dryer or even a wall paper remover steamer to heat the spot. I like to use an iron. You take a white terry cloth rag or towel, wet it and lay it over the spot. Next you apply heat, if you choose the iron be careful not to burn your carpet and check the spot often. Once it heats up the spot should disappear pretty quickly. The rag might turn a little yellow this is normal.
You need to rinse the spot. You can use a carpet cleaning machine if you own one or sometimes even a better choice is a wet dry shop vac. Whatever you do don't use your vacuum cleaner you will destroy it. Just rinse the spot clean water is fine. Now your spot should be gone for good.
I recommend calling a professional cleaner to do this for you, but times are tight and it is possible to do this yourself be careful and follow the manufactures directions. You don't want to make things worse.