Vitamin C is truly a medicine to take everywhere you go. I've used it for a spider bite I got while canoeing down a creek. My arm swelled and hurt and I didn't realize why at first. It finally dawned on me that I had brushed a limb at the start of the trip and spiders galore fell in the boat with me. Evidently one bit me!
I took 3-4G every 1.5 hours or so after getting home and continued the next day. Never got any signs of overdosing ie gas or diarrhea. I estimate I took 40G over 24 hours! It killed most of the swelling by nightfall the day of the trip!
Also had an employee get stung by a wasp. He told me the last time he got bit he had to go to the hospital. I gave him 5G and sent let him leave. He told me in an hour or so the pain and swelling had diminished greatly. He didn't have anymore vitamin C but he didn't need to visit the hospital!
Vitamin C for Insect Bites and Allergies: I had a spider bite once that swelled on my forearm like a half-egg under the skin. I took 3-4G of ascorbic acid, the cheap Vitamin C from Sams club, about once every hour and a half or so. By dark the swelling was down to maybe 10%. I continued overnight and all day the next day. During that time, while in the yard working, I felt something on my arm. I looked down to see a "fireant" biting feverishly the back of my hand. I assumed there must be something wrong with him as I didn't feel any burning. Another one bit me later with the same results. I only noticed a feeling like something was crawling on me. The wounds never swelled, turned red or itched! It must have been the massive doses of C circulating in my blood.
I estimated I consumed about 40 grams of C over a 24hr period. Normally that much C will give you severe diarrhea and gas! I had neither.
I also take it for severe allergy flareups with great and quick relief, though only last for 2-4 hours, depending on the intensity of the allergen.