Turmeric is a food, so it doesn't really matter how much you consume. (I wouldn't eat a POUND of it every day, you might turn yellow. LOL!) People who eat curry every day probably take in way more than any of us would taking it as a medicine. I think what Lynn meant by "shots" is a bit of turmeric powder mixed into milk (or some other liquid, but milk is most common). Adding a little black pepper makes it even more effective.
To my knowledge, turmeric doesn't become ineffective over time, or negative. There are some others that should only be taken for a couple of weeks at a time, then a week or two off, then back on again, such as echinacea and valerian. Those are the only two I can think of off the top of my head this early in the day. They WILL become less effective over time, but give it a week or two break and then they're good again. Turmeric isn't one of those, but it IS a great anti-inflammatory. It has been said, and I have no proof other than one of my herb books cites "studies," that it's more effective than cortisone shots. It's not a pain-reliever per se, but most pain is caused by inflammation, so reduce the inflammation and the pain level goes down. Anyway, it's a good, safe herb that actually does a lot more than reduce inflammation, but that's the reason most people take it. 
