What Does Causes Foul Smelling Discharge From Anus?

Hi.. I have a smelly liquid discharge from my anus. I exercise regularly and used to do a lot of weight exercises but I have stopped now because of this problem. I sometimes get blood in the stool and pain when I hold it for a long time otherwise its normal. I thought it was hemorrhoids so I started taking venapro but it didn t help either. Can you please suggest something ?