What color is the blood?
Do you have any history of constipation?
Have you had a fever?
Fresh red blood is usually a sign of hemorrhoids (piles). These can be painful and irritating but are not normally something to be concerned about.
Diet is a factor in hemorrhoids due to link with constipation. The important thing is to avoid constipation before it starts so eating plenty of fruit, veg, fiber and drinking 8 glasses of water a day is essential. Other lifestyle matters include being less sedentary, increase exercise.
However fresh red blood with diarrhea may indicate a more serious food poisoning or inflammatory bowel event so you need to make an appointment with your doctor as soon as possible to take a full history and also consider a stool sample analysis.
I will be off line for about an hour but will check back in as soon as possible..