Hello I'm 23 M , 173 cm and 63 kg I have seen some changes in my stool consistency for past 4 months so started taking fibers from then onwards and  I saw a good difference in my stool but before 1 week I saw blood only stool dark purple (beet root ) colour on the surface after that week I had severe constipation but no blood now I visited gastro and he performed proctoscopy to find whether I have hemorrhoids but it was normal no blood traces ...I fear that it could be from the tumour or cancer polyps .