Small amounts of blood in a rat’s urine and from the vaginal opening are one of the most commonly reported complaints from rat owners. Female rats do not menstruate, so any blood coming from this area indicates that something is wrong. The most common causes of blood in the urine or bleeding from this area are a uterine tumor, a urinary tract infection (UTI), or processes involved in pregnancy and labor. Assuming that your rat has not come in contact with a male rat, we can rule out the last cause. Both dribbling of urine and small amounts of blood in the urine can indicate both a urinary tract infection and a uterine tumor. However, given that one of these symptoms has been present for a while and your rat shows no other signs of illness, it is likely that your rat has a urinary tract infection. However, you need to have your rat thoroughly examined by your vet for the presence of a tumor. If he feels that a UTI is the probable cause, a course of antibiotics should clear this up.