I've heard that drinking coffee and grapefruit juice at around the same time can extend the effects of caffeine. Is this true? I know that grapefruits can increase the bioavailability of some drugs... what about caffeine? Is this at all dangerous?

I frequently hear that beverages with caffeine or alcohol are not good for replenishing fluids and preventing dehydration. But in reality aren't they just a bit less effective at hydrating your body than other beverages? In other words, if you were stuck in the desert with nothing to drink but beer, coffee and cola, would you actually be worse off and die of thirst sooner if you drank these beverages versus not drinking anything at all?

1) I have had acid coming up my throat from my stomach for the last 3 weeks. It comes up and just burns my throat. What is it? Do I have an ulcer? By the way, I get 3 hours of sleep a night, and my roommate doesn't help the situation.

2) I have recently asked you about my would be ulcer. I shall pose the question again. Lately I have this damn acid coming up my throat. I've been under a lot of stress and have strange sleeping habits. I am also drinking a lot of coffee. I drink about 5 cups of coffee a day and my roommate isn't exactly stress relieving. I go to bed about 3:30am and wake up about 5:45am for crew. Am I dying? Do I have an ulcer? What's wrong with me?

My partner suffers from mild social anxiety. Is it possible that this disorder can be aggravated by stimulants such as coffee? I have noticed that on days he drinks lots of coffee, the disorder seems worse, and he is more uncomfortable.

Please help! If we can eliminate possible aggravates of the disorder, he would be so much happier!