Just wondering, could a massive dose of vitamin C do as described in this article?
It sure strikes me as unlikely. Any substance is potentially toxic in high enough quantities and perhaps vitamin C causes neurological problems if you take enough. But vitamin C is pretty inoccuous; studies have been done on people taking as much as 20 grams per day - 200-some times the recommended daily value - and the worst it caused was diarrhea.
Vitamin C is water soluble. Your body dumps any extra you take. The behavior and the vitamin intake was likely a coincidence.
The behavior your article discribes sounds more like schizophrenia.
My first thought was that maybe the terrible diarrhea he would surely be experiencing was the actual cause of the hallucinations 
Vitamin C is not a hallucinogen*.
He’d already been exhibiting symptoms typical of schizophrenia (whether drug-induced or not); taking even a “massive” dose of vitamin C would not intensify those symptoms.
*if it was, the pharmacies wouldn’t be able to keep it in stock. And Linus Pauling would be known as the Mad Tripper of all time. 
The Erowid vaults have a couple of entries claiming that Vitamin C “enhances” the effects of other drugs - one for marijuana, one for Diphenhydramine. (The second one was a total dumbass, and took 11 grams of Vit. C at once - enough to burn holes in his stomach lining - he puked up rubbery bits of stomach before going to the hospital.)
But nothing on Vitamin C alone. And believe me, if you can smoke it, inject it, rub it or eat it, someone will write about it on Erowid.
Eleven grams is enough to put holes in your stomach lining? I have a hard time believing that’s accurate. That sounds like, well, it sounds sort of typical for what you find on Erowid. Vitamin C simply isn’t that acidic, and eleven grams isn’t that much. That seems really dubious to me.
Pure ascorbic acid, IIRC, has a pH of 3.5. The nutritional supplements are buffered with binders to have a fairly neutral pH. The type of idiots posting to Erowid vaults are the kind to exaggerate and make stuff up, but they are also the kind to have unbuffered ascorbic acid laying around the house or somesuch.
Quite possibly dubious. Or quite possibly I’ve forgotten my metric conversions. He took 11,000 mg (from fruit juices and EmergenC packets). That’s 11 grams, right? Oh, waitaminute. I missed that he took an additional box of cold pills, so it was a total of 1150 mg of diphenhydramine as well - enough in an of itself to cause at least minor stomach upset!
He writes:
I take everything on Erowid with a glacier of salt. But I mostly remain confident that Vit. C. is not a hallucinogen - and NOT being on Erowid supports that. These are guys who get high off fire ants and coffee, and even THEY don’t think Vit. C is a hallucinogen.
The pH of the contents of your stomach is generally lower than that. In fact, the pH of a lot of foods are in that range - according to this site, at least. The question is what the pKa of vitamin C is, since pH is actually the property of a solution, not a substance - it only makes sense to describe the pH of an aqueous solution of an acid, and the pH then obviously depends on the concentration. Google is telling me vitamin C has a pKa of around 4.2, which makes it not a particularly strong acid. If you took eleven grams on an absolutely empty stomach, it might cause some stomach upset but I really am doubtful that it would actually cause you to vomit up part of your stomach lining.
Wow, it’s not everybody who can tell stomach lining from, say, food or drug capsule fragments.
Taking large doses of vitamin C is highly unlikely to cause major stomach upset, much less burn out your gastric mucosa (if this guy was really vomiting up chunks of “stomach lining”, he’d be a candidate for hospital admission at the least, and not sent home after just an EKG and CBC (“blood test”). Megadosing on vitamin C is not completely innocuous (there have been cases of kidney stones reported with chronic high doses), but the chunks-of-stomach stuff is way out there.
Incidentally, alt health forums are full of stories from people who’ve administered colon or liver “flushes” to themselves, and who imagine they’ve passed gallstones, toxic waste, rubber erasers they ate in second grade etc. - there are photos galore online. What they really pooped out was mucus (or face it, poop - people are not very good at recognizing what emerges from their G.I. tract), but it makes for entertaining reading). :dubious:
Stomach lining isn’t “rubbery” it’s more like strands of jelly fish when it’s sloughed. Also, there would be massive bleeding along with it.
It’s a life threatening emergency.
My granny’s recipe for Lemonade involved a packet of Citric acid and half a packet of Tartaric acid in a big bowl of Lemon juice/sugar water mix. Dipping your finger in either packet and tasting it would just produce the typical sour-food grimace and a very strong sour taste, with no harmful effects other than to tooth enamel. No chemical burns, no hallucinations. From experience, I would agree that puke is far more acidic, corrosive and generally unpleasant than neat citric acid.
And if it was a hallucinogen, kiddies would have been tripping out on sherbet for the last few generations - I’m sure people would have noticed.
I asked as my Mum told me much the same, take too much and the body sends it out with your urine.
His life story leads one to believe he was schizophrenic 
As others have mentioned, probably not. However, it is possible that Dick was confusing vitamin C with amphetamines, which he did use in large quantities.
Both Valis and Radio Free Albemuth are set at the time Dick saw his pink lasers.
FTR, the opening line of RFA may indicate where Dicks mind may have been at the time.