chlamydia infection
"I was prescribed 1g of azithromycin in 2 500mg pills. My doctor allowed me to take them an hour apart as to try to avoid some stomach upset. I took them at 8pm with dinner, and was fine till about midnight. I got pretty bad stomach cramps and diarrhea consistently throughout the night.  By the next morning though everything had subsided and I was fine. Ate normally, felt no side effects. I began feeling better after a day and was negative upon re-test. Medicines work good, you just have to put up with a few unpleasant side effects sometimes."