Blood in a cat's urine can be a sign of many things and there really is no home remedy for this problem. The first thing you need to do is get your cat to the veterinarian. Your veterinarian might suggest you bring the cat in, or bring in a urine sample.
How do I know if my Cat has Blood in its Urine?
If your cat is not provided with a cat litter box in the home it may be some time before you notice health problems. You may notice your cat peeing in the home, on carpets, towels, clothing, even pieces of cardboard. What happens is that the cat is in pain when urinating, it associates urinating with the litter box (or where ever it normally pees) and soon stops using that location. You may even hear your cat meowing while urinating. Other times the irritation is so painful the cat tries to pee where ever it happens to be at the time.
You may notice drops of blood on your floor, near the litter box, or in the litter box. This is one reason why it is a good idea for adults to check the litter box, kids might not realize how important it is to note these things.
What to do if your Cat has Blood in its Urine
Certainly if the cat has other symptoms, such as loss of appetite, loss of weight, or vomiting, the situation should be considered as an emergency. If your cat seems to be licking its genitals more often than usual this could be a sign of a problem. Blood in the urine can indicate many problems, from diabetes, to a urinary tract infection (UTI), to a kidney problems. In some cases the problem could be life threatening, as such, if you see blood in your cat's urine, and particularly if there are other symptoms, your cat should be taken to the veterinarian immediately (not just a urine sample).
Your veterinarian will want to examine the cat, they may take blood to test for diabetes. They will look at the urine sample to check for crystals, bacteria, and so forth.
The correct term for blood in the urine is hematuria.
Problems related to the urinary tract are more common in older cats, particularly males. Female cats who are not spayed can have other health issues in addition to urinary tract health problems, that could show up as blood in their litter box.
Note that because male cats have a narrow urethra they are more often at risk for a blockage which can be life threatening.
How to Prevent Urinary Tract Problems in Cats
Proper feeding can help prevent urinary tract problems in cats, in particular owners need to select a healthy cat food low in Magnesium. While many people will debate if cat's should be fed only dry food (to clean their teeth) or only canned food (for urinary tract health) it can be best to do both; offering dry food and feeding small helpings of canned food too. The canned food can be once or twice a day, a teaspoon per feeding, with water added to make a soup. The water helps flush the urinary tract keeping it healthy. Note that canned food marked as chunks in gravy should not be fed to cats, gravy is carbohydrates and would contribute to a cat developing diabetes.
Feeding a proper, meat based, diet is very important, however many commercial cat foods are loaded with cheap filler (corn, by-products). The healthy diet will help reduce the cat's chances for developing diabetes.
You can also encourage the cat to drink more water by keeping their water fresh, cats are fussy, they do not like to drink water that smells like dust.
Giving water in a stainless steel bowl, or ceramic bowl, is better that offering it from a plastic bowl as the plastic bowl could contain bacteria.
Making sure the cat always has a clean litter box will also help prevent problems as many cats hold their urine if their litter box is too dirty, and holding their urine can cause problems.
Note that none of these tips should be considered as a “cure” for cat's with urinary tract problems, again it is important that the cat see a veterinarian if it is urinating in the house and particularly if there is any blood in the urine.