Recently I ate a sandwich made from a left over steak from the evening before. Problem was it wasn't keep cool enough and I didn't eat it till late afternoon. Bingo, my innards begin to hurt in about a half hour and over the next couple of hours I got sicker and sicker till I could hardly stand. I had got food poisoning!
When she realized what my malady was caused by, my fair lady put two level tablespoons of powdered charcoal into a glass of cold water and ordered me to drink it. Within 15 minutes I could feel myself improving rapidly and within a half hour I was back to normal.
The charcoal she used was bought from a health food store, but charcoal tablets are also available in many drug stores and healthfood stores, and might be a bit easier to take. It's uses include almost any kind of poisoning and any stomach/intestinal flue, or loose bowels, and the effect is as quick as I got in most cases. For most insect stings, a bit of crushed charcoal plastered on with a bit of your own saliva will stop the pain and swelling in minutes. If nothing else is available, I'd definately use it for snakebite too, but hang a good glob on.
If you run into a problem and don't have charcoal, just burn any wood available till the sticks break easily, cool in clean water and eat it like a Snicker bar, or crush and drink in water.
To purify water, drop several pieces into a pot of water and bring to a boil for a few minutes. Let cool and drink the dark water. Charcoal will pick up almost every toxic chemical known from water, as well as most microbial toxins.
Best wood to use is pine, or willow, but use anything available, as any wood will work fine.
Don't forget it. Many hunts are ruined by food poisoning, from resturant food or things not handled right in camp, and a bit of charcoal could save the outing in minutes.