I have vitamin C dietary supplements. How many can I take? They are 500 mg each. It's the "nature made" brand.

Vitamin C. Generally for daily dose 500 mg to 1000mg should be fine. I generally reserve extra C for stress or for example for cold etc. In that case I take one gram three times per day.
Vitamin . Vitamin c is generally considered a very safe supplement, and has been studied by medical researchers in doses up to 10, 000 mg (that would be 20 of the capsules you say you have) per day. The us recommended daily allowance for vitamin c is 90 mg/day for men, 75 mg/day for women. So if you took one 500 mg tablet per day you would be getting well over the daily minimum amount suggested by the fda. Exactly how much you should take is controversial. Recommendations range from the rda above to 2, 000 mg per day (and some are higher). Looking over most of the medical research, most benefits are thought to be attained at a dose of 400-500 mg/day, or one of your tablets. There is very little risk of anything bad happening to you from too much vitamin c. People often get diarrhea at higher doses (in the 1000-2000 mg/day range), but this goes away when the dose is reduced. A good source of information about vitamin c is the linus pauling institute at oregon state university (google them).