Thank you for the query.
Constipations and loose motion
appearing alternately can indicate serious pathology in large intestine (colon cancer
). Positive result of the fecal occult blood test
makes it even more possible. That is why the next step you should take is colonoscopy
and it should be done as soon as possible.
If your stools are black like a tar, also upper GI endoscopy should be performed.
Hope this will help.