pneumonia
"I have been ill for three weeks. Doctor gave me a prescription for doxycycline, but there was no improvement. On a Sunday I went to a walk-on clinic. They sent me straight to the hospital. After a plethora of wasted tests, they decided that I had bronchitis and sinusitis. This does not sound terribly severe, but I was so sick I didn't know how to cope any more. Within 24 hours of first dose, I am much better. No side effects are evident."