Hi, I started celexa 3 days ago. Last night I had bright red color in my stool. It was a decent amount. Could that be a dangerous side effect of the celexa? Other symptoms, I don t have any known. I never have noticed any blood in my stool, or dark colored stool either. I m worried about it. Nothing in my diet has changed other than the celexa. I also take clonazapam. I don t think there are any issues mixing those together, but I m not a dr. So any advice would be appreciated.