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 markedly mitigates diarrhea symptoms and weight loss in male rats with colitis [1]. Furthermore, administration of 10 mg/kg/day intraperitoneally over five days significantly improves oxidative stress parameters and enhances antioxidant enzyme functions in forty-five Sprague-Dawley rats, weighing between 200 to 250 g, with intact esophagi [2].