Azithromycin
"I found out I had chlamydia  on Tuesday and took two 500mg tablets.. I read the side effects and got a little scared but didn't think much of it because I usually have a strong stomach. I had taken the pill at around 5pm and by 9pm I had the worst stomach pain and diarrhea. Although the diarrhea did stop, it is now Friday 8:50am and I have vomited 3 times. I'm hoping these side effects stop soon and clear me from infections."