What follows is purely anecdotal evidence. In fact, it's pretty much the definition of anecdotal evidence. If you look up "anecdotal evidence" in the dictionary, you will find a link to this post.
Still, it's interesting and, as newspapers used to say in the days when they printed stories they couldn't verify, "important if true."
Since Tuesday I've had a sinus infection. On Thursday, having realized it wasn't just an allergy or a cold, I went to a doctor and got a prescription for antibiotics, which I am faithfully taking. The antibiotics cleared up most of the symptoms within a couple of days. But one symptom persisted and in fact got worse - a continuous heavy cough.
I had a sinus infection last year, and the same thing happened. The cough persisted long after the other symptoms, and even after I had completed my course of antibiotics. In that case I had to go back to the doctor for a second, stronger course.
This time the cough was especially bad. I could hardly sleep at all. On Saturday night I was awake until the wee hours of the morning (Sunday morning). I finally got about two hours of sleep.
During my period of insomnia I went online and searched for "cough" + "remedy." Various herbal teas and other concoctions were offered. I'd tried some of these last time with no effect.
One idea I hadn't tried involved Vitamin C. The suggestion was to take a very large dose of C in ascorbate form. Ascorbate is said to be more efficiently absorbed by the body than the more common ascorbic acid.
I was skeptical. Isn't megavitamin therapy a crock?
On Sunday morning I dragged myself to the local drugstore and bought some food and other essentials, but I did not buy any Vitamin C. I thought it would be a waste of money.
But when the cough persisted into the afternoon, I got desperate. Feeling foolish, I returned to the drugstore and hunted among the Vitamin C products until I found one that contained C in ascorbate form. The brand is Ester-C. I bought the 1000-mg variety. (The RDA for Vitamin C is only 60 mg.)
Still coughing when I got home, I immediately took three of the Ester-C pills. That's 3000 mg of C. This was at 3:30. Within five minutes my cough stopped. (I kept a journal to ensure accuracy of recollection.)
An hour later, at 4:30, I started to cough again. I took an additional 2000 mg of C. This brought the total dosage of C to 5000 mg. The cough stopped.
Moreover, I felt a rush of energy. I decided to go for a "short walk." The short walk turned out to last almost two hours, during which time I hiked up and down the twisting, hilly streets in my neighborhood. I had not had this much energy since coming down with sinusitis. (I'm not even sure I had this much energy when I was healthy.)
At 6:30, back from my walk, I was starting to cough again. I took 2000 mg of C. The cough stopped and remained quiet for nearly four hours.
At 10:15 it started to make a comeback. I took 2000 mg of C, and another 1000 mg at 10:30 because I wasn't sure the first dose was enough. After that, the cough was quiet.
But now the acid test was approaching: bedtime. This is when the cough was always at its worst. Would I start coughing as soon as I lay down?
Rather nervously I reclined on the couch at 11 PM. After a short time - still cough-free - I fell asleep. I woke up at 12:30 PM today, having slept for more than thirteen hours. And I still wasn't coughing.
Could this be a coincidence? I think it's unlikely. The cough disappeared almost immediately after I took the first megadose, and each time it started to return, another megadose suppressed it.
How about the placebo effect? I can't rule this out. Although consciously I was skeptical, subconsciously I may have expected the treatment to work. On the other hand, I had tried various other remedies for the cough, and none of them had any effect. Why would the outcome be different in this case?
I think the most likely explanation is that the Vitamin C really did knock out the cough. I can't prove it, but I'm passing along the information for what it may be worth.
Incidentally, I should point out that the 1000-mg Ester-C pills are very large, and some people may have trouble swallowing them. Ester-C is available in 500-mg form as well, and those pills are smaller and easier to swallow.