What Causes Loose Stools With Spot Of Blood In A Baby?

Hi for the past 3days my toddler has been passing loose stools which is unusual and more frequent than usual. Today he pass it with a little mucus and what looked like a tiny spot of blood. He did have a flu last month and was on medication for it. He normally poops 1in every 2days or so with no problem. Can you say what iswrong