I've had a recent flare-up of my IBS recently. My diarrhea is worse, as are a few other IBS symptoms. I've been on Mucinex (guaifenesin) 1,800mg a day for a blocked eustachian tube for about a month and I'm starting to wonder if it's causing this flare-up. Has anyone ever been on guaifenesin and has it affected your IBS? Thanks.