Common question from new rat owners: My rat's eyes are bleeding what should I do? Are you sure it's really blood? Usually the answer is no it isn't. The red tears of rats look like blood but it's actually a substance called porphyrin.

It's not normal to see these "red tears" often. It's normal to see a bit of porphyrin staining when they first wake up from a long sleep; it's normal to see a bit of it when they've been grooming. You may see pink staining on their fur from time to time, this is nothing to be alarmed about.

What does it mean when you see this porphyrin? Porphyrin is not a serious problem itself, but seeing it does indicate that a problem may be happening. Anything from minor stress to major illness can cause porphyrin to flow from their eyes. Poor quality bedding, unclean housing, stress from handling them too roughly, stress from a home that's too noisy, these among others are all possible minor reasons to see it. More serious reasons are the onset of any type of disease.

How do you know it's not blood? Porphyrin will fluoresce to a bright pink/magenta color under ultraviolet light, blood will not. You can check this yourself by keeping an ultraviolet light bulb, which sell for anywhere from one to ten dollars. When you see what you think is blood on them or on surfaces in the cage, an ultraviolet or "black" light is a handy item to have at home.

If you see porphyrin flowing heavily from one eye but not the other, the problem is most likely a blocked tear duct. Flush the eye with non-medicated eyewash, which you can buy at any store that sells products for use in human eyes. If flushing doesn't stop the flow, see your vet.

If you see porphyrin often you'll most likely see other signs of disease such as sneezing, raspy breathing, general failure to thrive. In that case it's best to see your veterinarian to find out if there is any type of problem which may require treatment.

Written by Jan Mcarthur, R.V.T.