Four. The first two times were when I was a teenager and had such bad menstrual cramps that I was about to pass out (I later went on birth control, so that's no longer an issue). The two most recent times was four summers ago when I got unbelievably sick. I couldn't even get out of bed (I tried to get up to take a shower but I literally had to drag myself on the floor to even get to the bathroom because I felt so weak) and I had an almost constant high fever. When it got to 104 despite me taking all of the Tylenol that I could, I went to the ER because that's when a fever is considered pretty serious and nearing the point where it could cause brain damage. Then I ended up back at the ER just two days later, after I had started to think that I was getting better. Up until that point, I had only been having the high fever, extreme fatigue/weakness and a severe headache, and that stuff was starting to go away, but then suddenly, I woke up that day throwing up and I couldn't keep anything down (not even water... I'd take one sip and start dry heaving). Even though it seemed like the actual infection I had was starting to go away, it's like it just attacked my liver, because upon going back to the ER, they found that my liver enzymes were extremely elevated, and that seemed to be what was making me throw up. It was insane...they never did even figure out what exactly it was. I finally did recover fully after about a week. I don't know if it was just an especially awful strain of the flu (even though it was summertime so that would be pretty unusual) or if it could have been something from a mosquito...they tested me for West Nile Virus but it came back negative. Someone told me that my symptoms sounded a lot like Dengue Fever when I described them later. But then again, I hadn't traveled anywhere foreign, and it's really rare to get one of those mosquito-borne diseases within the US or any other developed country, so I don't know. Whatever it was, I hope I'm immune to it after having it once, because I seriously had ever felt so miserable in my life and I hope to never experience it again! And yeah, I was an overly cautious and not very adventurous kid, so I definitely never did anything crazy to land myself in the ER when I was a child.