Mercaptoethylguanidine (MEG) dihydrobromide is a selective inducible nitric oxide synthase inhibitor and peroxynitrite scavenger with potential for inflammatory bowel diseases research.

Mercaptoethylguanidine (MEG; 10 mg/kg i.v. b. i.d.) dihydrobromide significantly reduces the appearance of diarrhea and the loss of body weight in male rats with colitis [1]. Mercaptoethylguanidine (10 mg/kg/day; ip; for 5 days) dihydrobromide ameliorates oxidative stress parameters and antioxidant enzyme activities in forty-five Sprague-Dawley rats weighing 200 to 250 g with esophagus uninjured [2].