I was given a prescription of Biaxin 500mg to treat a severe respiratory infection. I became quite ill after the second pill. I had vomiting, diarrhea, high fever,a tremendous back pain, lack of sleep and appetite. The worst part is that it also came with a huge headache by the third day, and could not take anything for it or keep anything down, so dehydration became a factor. A call to my Dr. went with the explanation that this happens sometimes. New medication was called in. I don't understand as to why we are given all this new drugs that are so ineffective, are dangerous and more expensive. We are all little guinea pigs. I must note the three years ago I had pneumonia, which this turned out to be, and I felt better within days. Today we are not so lucky. What a shame!