When is rectal bleeding cause for alarm?

Any time: Rectal bleeding is never normal, hemorrhoids, fissure, ulcer, cancer, diverticular disease. See your pcp.

Sometimes: More worrisome features are darker blood, blood mixed with mucous, chronic bleeding worsening and persistent and recurring bleeding and bleeding associated with other GI symptoms, and increasing age. Though any or none of these factors could be a sign which needs evaluation if persistent. Hope this helps.