Hello,

I took neomycin for SIBO last year. My stomach was decently messed up for the 4 weeks, but not noticeably more so than being on any conventional antibiotic. No issues with nausea but of course YMMV.

You may already know about this "trick" for treating SIBO but during the first 1-4 days just eat however you consider "normal" to be, and then past that start adding in food that you have been avoiding due to SIBO. The idea is to let the bacteria feast so that they become more susceptible to the drug (versus the unfortunate situation where they remain dormant and stay around to repopulate afterwards). Good luck!