Hello I appreciate your concern and I will try to help you out in best possible way This can be caused by food poisoning or gastroenteritis, colitis or food allergy. itching of anus can be related to fissure in anus or hemorrhoids I would like further information to help you better like Your age and relevant medical history like diabetes or liver disease have you seen blood in stool? have you taken any medicines or adulterated good Since how long you have this problem? I would advise you to consult your doctor for baseline investigation to assess the amount of blood loss by doing blood for hemoglobin and CBC meanwhile try to avoid constipation by taking liquid paraffin like stool softeners Have dietary fiber to increase bulk of the stool. have lots of fresh fruits and steamed vegetables Avoid smoking and alcohol it could be dangerous for you Wash your hands with antiseptic soap or solution to maintain good hygiene Avoid fatty fried junk and cold food If you can provide me more details like your age and presence of any other metabolic illness like diabetes or thyroid and liver disease, I will be able to help you better In my opinion you should consult a gastroenterologist for an colonoscopy if need be. Hope this answers your question Wish you good health