Azithromycin
"Honestly, this has been the worst antibiotic I have taken. SIDE EFFECT WISE! 35 minutes after taking four , 250mg pills, I felt extremely ill and ending up throwing up and  experiencing instant  diarrhea. I'm not one to complain because normally my stomach acts very well on antibiotics. I'm currently awake now dealing with really loud gurgling noises from my stomach. Hopefully this means the medicine is in full effect."