I did, fairly regularly, until my recent medical issues. Or I should say "I tried." About half the time my iron levels were too low. But when I asked my oncologist last visit, his response was "I'm not sure" (My tumor was RARE-- he's only seen this type 3 times. And Long Island is a magnet for breast cancer.) So I no longer donate. But I feel guilty every time there's a blood drive, like I should explain that I'm not being selfish.