Antibiotic associated diarrhoea
I've just added a page to my site; it is about antibiotic-associated diarrhoea. I've not come across this in the treatment of MS with antibiotics; doxycycline and azithromycin seem to be uncommon causes of AAD, and, paradoxically, metronidazole, which is used for treating AAD, can, on rare occasions, cause it. Personally, I don't think it's a big issue, but it would be irresponsible not to mention it. Diarrhoea is quite common during the antibiotic treatment of chronic C. pneumoniae infection, possibly because of infection of the autonomic nervous system which innervates the gut.