Since two weeks , im having red stool . i started drinking fresh beets juice. i have no pain in abdominal. is it because of beets or any other serious?

Maybe the beets but: This may just be hemorrhoids from straining but bleeding from rectum (brbpr) may also indicate anal fissures, proctitis (due to infection, inflammatory bowel disease, radiation therapy, stercoral ulcers, rectal prolapse, trauma, etc.) or a bleeding source further upstream. Depending on your age, risk factors, current medication (aspirin, nsaids, anticoagulants can cause bleeding), see your doctor.