I read this :
Metronidazole (Flagyl) and
ciprofloxacin (Cipro) are two antibiotic drugs that may be used to treat IBD in children. Antibiotics may be used for more mild cases of IBD and are often used in conjunction with other medications, such as the 5-ASA drugs. Metronidazole may be used in particular for perianal Crohn's disease (disease that is located in the anus, rectum, and vaginal areas) or in patients with Crohn's disease complicated by
perianal fistulas. Ciprofloxacin may be used as an alternative to metronidazole in perianal Crohn's disease, and it also may be used to treat milder cases of left-sided ulcerative colitis.
Side effects of metronidazole include diarrhea, vomiting, and numbness in the hands and feet which may be from reversible nerve damage (peripheral neuropathy). Metronidazole should not be taken with alcoholic drinks, as it can cause severe nausea and vomiting. Ciprofloxacin is associated with side effects such as nausea, vomiting, diarrhea,
I know I'm not a child but I'm sure it applies to adults as well.