Brief Answer:
Please get clinical examination as advised

Detailed Answer:
Hi.
Thanks for your query, albeit small and specific.

The commonest causes of bleeding per-rectum while passing motion are:
- Piles (Hemorrhoids), usually painless bleeding, comes along the stool and may fall down drop by drop later on.
- Fissure in ano, the bleeding comes as streak with the stool, may fall as few drops and always painful.
- Polyp
- Cancer and so on.

I would advise you the following:
The best way in such a case is always to have a clinical evaluation, actual pre-rectal examination, proctoscopy to start with. Further tests as required/advised by the examining Surgeon.
This is so important to have the earliest possible and the correct diagnosis.

I hope this answer helps you, please feel free to ask for further relevant queries if you need to or if you feel that there is a gap of communication.

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