I don't know if I have IBS, but my problems were almost certainly started by taking Cirpfloxican, a drug originally developed to kill anthrax. After doing some research, I'll never willingly accept another fluoroquinoline drug again - highly toxic, and linked to many conditions like tendon rupture, nervous system damage, etc, that have left many debilitated with chronic pain, nerve damage, and GI tract issues. I only took it for 5 days, and got a skin rash, had a few days of muscle aches, severely wrecked my gut, and now over three months with infuriating and unexplained rectal discomfort that I'm still attempting to treat with fungal meds.
If a drug could cause something like IBS, then any fluoroquinolone would do the trick. A lot of folks have developed extreme food sensitives following a dose of that drug. Personally, I had no idea any antibiotic could be so toxic and so dangerous. I simply trusted the doctor's prescription, not always a great idea.