My 6yr Old Just Finished Zithromax And Was Put On

My 6yr old just finished Zithromax and was put on Augmentin for an ear infection. His bm has been orange and watery and today he had 2 bm formed brown but when I wiped him it looked like mucous like blood. I am not sure though. I was trying to think of what he had to eat or drink, and the only red thing has been Hawaiian punch. So, I am not sure if I should be concerned or not? Any advice?