# Why Is My Small Pet Bleeding From the Bottom? If your guinea pig is bleeding from her bottom, the blood is coming from one of three places: the urinary tract, the reproductive tract, or the rectum and anus. Each has a different set of likely causes, and some are emergencies. The color, amount, and timing of the blood, plus your guinea pig's other symptoms, help tell them apart. This article is educational and is not a substitute for veterinary diagnosis or treatment. ## Quick Answer - Blood at the bottom is not normal in guinea pigs and always deserves a veterinary call. - Bright red drips after urination usually point to the urinary tract, where bladder stones are common in guinea pigs [1]. - Blood mixed with vaginal discharge in an unspayed female can signal a uterine problem, including infection or cancer [2][3]. - Blood on the stool or around the anus often points to digestive or rectal disease, and guinea pigs with digestive upset can decline fast [4]. - Any guinea pig that is not eating, is hunched, or is passing large amounts of blood needs to be seen the same day. ## What Bleeding From the Bottom Looks Like in Guinea Pigs Owners describe this in different ways. You might see red smears on bedding, a stained rear end, drops of blood after your guinea pig urinates, or blood mixed into the stool. Sometimes the blood is bright red. Sometimes it is dark and looks like coffee grounds. Sometimes it is watery and pink, mixed with discharge. Normal guinea pig urine varies in color. It can look milky or chalky because guinea pigs excrete calcium in their urine. Normal urine can also darken to orange or reddish brown after it sits on bedding and oxidizes. That color change is not blood. True blood is usually brighter, and it often comes with straining, crying out, or a change in how often your guinea pig urinates. Normal guinea pig droppings are well formed and fairly uniform. A healthy rear end is clean and dry. Staining around the rear end is a sign of digestive upset, and guinea pigs with digestive disease may also have diarrhea, small stools, weight loss, low energy, and dehydration [4]. ## Why Is My Guinea Pig Bleeding From Her Bottom? The cause depends on which system is bleeding. The table below groups the main possibilities. | Cause | Typical clues | How urgent | |---|---|---| | Bladder stones (urolithiasis) | Straining to urinate, crying while urinating, small amounts of urine, blood at the end of urination | Urgent, same day | | Urinary tract infection | Frequent urination, bloody urine, discomfort | Urgent, same day | | Urethral diverticulum with a stone | A mass near the genital opening, difficulty urinating, blood in urine [5] | Urgent, same day | | Bladder tumor | Weeks of bloody urine that does not clear, stones ruled out [6] | Urgent, schedule quickly | | Uterine infection (endometritis) | Vaginal discharge that is bloody or pink, often persistent, sometimes a mass felt in the belly [2] | Emergency | | Uterine or ovarian tumor | Bloody discharge in an unspayed female, often middle aged or older [3] | Emergency | | Dental disease | Drooling, weight loss, mouth bleeding, trouble chewing [4] | Urgent, same day | | Digestive disease | Diarrhea, staining around the rear end, small stools, weight loss, weakness [4] | Urgent, same day | | Cancer of the blood or lymph system | Enlarged lymph nodes, weight loss, poor appetite, weakness [7] | Urgent, schedule quickly | ### Urinary Causes The urinary tract is the most common source of blood at the bottom in guinea pigs. Lower urinary tract disease is widespread in exotic companion mammals, and bladder stones are a major problem in guinea pigs [1]. Stones cause pain, straining, and blood in the urine. Some guinea pigs form stones inside a pouch near the urethra called a urethral diverticulum, which can trap stones and cause repeated episodes of bleeding and difficulty urinating [5]. Urinary tract infections cause similar signs. So do bladder tumors, which are uncommon but are being diagnosed more often. In reported cases, guinea pigs with bladder tumors often had prolonged bloody urine, and the tumor was only found after stones had been ruled out with imaging [6]. Late recognition is the main reason outcomes are poor, because by the time the tumor is found it is often large [6]. ### Reproductive Causes in Females If your guinea pig is female and not spayed, the uterus and ovaries are also possible sources. Uterine infection can cause a persistent vaginal discharge that is bloody or pink-tinged, and a mass may be felt in the lower abdomen [2]. In one reported case, a guinea pig with a uterine mass and ovarian cysts was brought in for suspected blood in the urine, and the true source was the uterus [3]. This is why the distinction matters. A female guinea pig with bloody discharge may look like she has a urinary problem when the bleeding is actually coming from the reproductive tract. Only a veterinarian can tell the difference. ### Rectal and Digestive Causes Bleeding from the rectum is less common than urinary bleeding, but it happens. Digestive disease in guinea pigs usually comes from an inappropriate diet or an infection, and signs include diarrhea, small stools, weight loss, low energy, poor appetite, and dehydration [4]. Some guinea pigs decline very quickly and die suddenly, while others show rough fur, staining around the rear end, a hunched posture, dull eyes, stomach pain, and weakness [4]. If you are comparing symptoms across species, the guides on [why a dog bleeds from the rectum](/knowledge/veterinary-medicine/symptom-guides/why-is-my-dog-bleeding-from-rectum-hge-vs-colitis-vs-polyps) and [dog diarrhea with blood and mucus](/knowledge/veterinary-medicine/digestive-and-urinary-care/dog-diarrhea-blood-mucus-causes) explain how vets sort out similar signs in dogs. The logic is similar, but the causes and the urgency are different in guinea pigs. ### Other Causes Worth Knowing Dental disease can cause bleeding around the mouth, and it also causes drooling, weight loss, and trouble eating [4]. If your guinea pig is dropping food or losing weight, dental problems may be part of the picture even if the blood you noticed is at the other end. Young guinea pigs can develop skin tumors or blood cancers such as leukemia, and many other cancers appear more often after 4 to 5 years of age [7]. Lymphosarcoma is a malignant cancer that can enlarge the lymph nodes, liver, or spleen, and the outlook is usually poor, with most affected guinea pigs living only weeks after diagnosis [7]. ## Red Flags That Mean Emergency Call an emergency veterinary hospital right away if you see any of these: - Large amounts of blood, or blood that keeps coming - A guinea pig that is not eating or drinking at all - A guinea pig that is hunched, grinding its teeth, or crying out - Straining to urinate with little or no urine coming out - A swollen or painful belly - Collapse, weakness, or trouble breathing - A guinea pig that feels cold to the touch Guinea pigs hide illness well. By the time they look sick, they are often already quite ill. Do not wait to see if it improves on its own. ## What You Can Safely Do at Home While You Wait Home care is about keeping your guinea pig stable until you can get veterinary care. It is not a treatment for the bleeding. - Keep your guinea pig warm and quiet. Move it to a small, clean enclosure with soft bedding so you can see new blood and monitor droppings and urine. - Offer fresh water and its normal food. Do not change the diet suddenly. If your guinea pig is not eating, tell the veterinarian, because guinea pigs that stop eating can go downhill fast. - Do not give any medication on your own. Never give antibiotics or pain relievers without veterinary direction. Doses depend on your guinea pig's weight and health, and your veterinarian will calculate them. - Do not try to remove a stone or express anything from the urinary opening. You can cause serious injury. - Take a photo of the blood and bedding. Note the time, the amount, and whether it appeared with urine or stool. This helps your veterinarian narrow down the source. - Call ahead. Tell the clinic you are bringing in a guinea pig with bleeding from the bottom so they can prepare. If your guinea pig is also scratching or chewing at itself and causing bleeding, the first aid principles in [dog licking paws making them bleed](/knowledge/veterinary-medicine/emergency-care/dog-licking-paws-making-them-bleed) can help you stop surface bleeding safely, but they do not apply to internal bleeding. ## What Your Veterinarian Will Check Your veterinarian will start with a full physical exam. They will look at the rear end, feel the abdomen for masses or a full bladder, check the teeth, and look at the lymph nodes in the neck, since these often enlarge with infection and can fill with pus [7]. Next comes testing. Urinalysis helps identify blood, crystals, and infection. Imaging is often the most useful step. Ultrasonography, computed tomography, and MRI have improved a great deal for exotic pets, and species-specific urinalysis values are now available [1]. If your veterinarian suspects a bladder tumor, ultrasound is the recommended next step once stones have been ruled out [6]. Blood work and tissue sampling help diagnose cancers such as lymphosarcoma [7]. If a uterine problem is suspected, imaging can show ovarian cysts and uterine masses, and surgery may be recommended to remove them [3]. Treatment depends on the cause. Stones may need surgery, and guinea pigs have a high rate of complications after bladder stone surgery, so your veterinarian will discuss the risks with you [1]. Infections need the right antibiotic at the right dose. Tumors may need surgery if they can be removed, and in one reported case a bladder tumor was removed successfully with no sign of recurrence one month later [6]. ## Preventing and Monitoring Bottom Bleeding You cannot prevent every cause, but you can lower the risk and catch problems earlier. - Feed a guinea pig diet with plenty of hay. Dental disease is linked to not enough chewing, and dental problems can lead to weight loss and other issues [4]. - Keep the diet consistent. Digestive problems usually stem from inappropriate diets or infections [4]. - Weigh your guinea pig weekly. Weight loss is one of the earliest signs of trouble. - Check the rear end daily. Look for staining, discharge, or blood. - Watch urination. Note any straining, crying, or changes in frequency. - Keep up routine veterinary visits, especially as your guinea pig gets older. Many cancers appear more often after 4 to 5 years of age [7]. If you have a dog as well, some of the same monitoring habits apply. The guide on [dog blood in stool but acting normal](/knowledge/veterinary-medicine/digestive-and-urinary-care/dog-blood-in-stool-acting-normal) explains why "acting normal" does not always mean "nothing is wrong." ## Limitations and When to Contact a Veterinarian This article cannot tell you what is causing the bleeding in your guinea pig. Only a veterinarian who examines your pet can do that. Individual cases need a veterinarian. Contact a veterinarian the same day if you see blood at the bottom, straining to urinate, a change in droppings, or any decrease in appetite. Go to an emergency clinic now if there is heavy bleeding, no urine production, collapse, trouble breathing, or a guinea pig that will not eat or drink. Schedule a routine visit soon if you have noticed intermittent blood over days or weeks, even if your guinea pig seems fine otherwise. Prolonged bloody urine that does not clear needs imaging, because late recognition of tumors leads to worse outcomes [6]. ## Frequently Asked Questions ### Can blood at the bottom be normal for a guinea pig? No. Blood is never normal in guinea pig urine or stool. Dark or reddish urine on bedding can be normal oxidation, but true blood, clots, or bloody discharge need veterinary attention. ### How do I tell if the blood is in the urine or the stool? Watch where it appears. Blood that shows up when your guinea pig urinates, or that drips from the urinary opening, points to the urinary tract. Blood mixed into droppings or smeared around the anus points to the digestive tract. A veterinarian can confirm the source with an exam and testing. ### Is bleeding from the bottom more serious in male or female guinea pigs? Both need urgent care. Females have an extra possible source, the uterus and ovaries, which can bleed from infection or tumors [2][3]. Males can develop urinary blockages from stones, which is also an emergency. ### Can I wait a day or two to see if the bleeding stops? No. Guinea pigs hide illness and can decline quickly. Digestive disease in particular can cause some guinea pigs to die suddenly [4]. Call your veterinarian today. ### What should I bring to the appointment? Bring a photo of the blood, a note of when it started and how often it appears, and a fresh stool sample if you can collect one. Also bring a list of everything your guinea pig eats, including hay, pellets, and treats, since diet is often part of the problem [4]. ## Related Articles - [Why Is My Guinea Pig Peeing Blood?](/knowledge/veterinary-medicine/small-mammal-care/guinea-pig-peeing-blood) - [Guinea Pig Diarrhea: Causes and What to Do](/knowledge/veterinary-medicine/small-mammal-care/guinea-pig-diarrhea-causes-treatment) - [Why Does My Small Pet Have a Bald Spot? Hair Loss in Hamsters, Rabbits, Rats and Guinea Pigs](/knowledge/veterinary-medicine/small-mammal-care/small-pet-bald-spot-hair-loss) - [Guinea Pig Adenovirus](/knowledge/viruses/pet-viruses/guinea-pig-adenovirus) - [Guinea Pig Cytomegalovirus](/knowledge/viruses/pet-viruses/guinea-pig-cytomegalovirus) ## References 1. [Update on Lower Urinary Disorders of Exotic Companion Mammals](https://pubmed.ncbi.nlm.nih.gov/41062376/). The veterinary clinics of North America. Exotic animal practice, 2026. 2. [Decidual Cell Reaction and Endometritis in a Guinea Pig](https://pubmed.ncbi.nlm.nih.gov/41468976/). Journal of the American Association for Laboratory Animal Science : JAALAS, 2025. 3. [Uterine choriocarcinoma associated with ovarian cysts in a Cavia porcellus: a clinical case](https://pubmed.ncbi.nlm.nih.gov/42245977/). Frontiers in veterinary science, 2026. 4. [Common Health Problems of Guinea Pigs - All Other Pets](https://www.merckvetmanual.com/all-other-pets/guinea-pigs/common-health-problems-of-guinea-pigs). Merck Veterinary Manual. 5. [Urethral diverticulum and urolithiasis in a female guinea pig (Cavia porcellus)](https://pubmed.ncbi.nlm.nih.gov/29154708/). Journal of the American Veterinary Medical Association, 2017. 6. [Primary Urinary Bladder Tumors in Three Guinea Pigs (Cavia Porcellus)](https://pubmed.ncbi.nlm.nih.gov/37607617/). Topics in companion animal medicine, 2023. 7. [General Medical Conditions of Guinea Pigs - All Other Pets](https://www.merckvetmanual.com/all-other-pets/guinea-pigs/general-medical-conditions-of-guinea-pigs). Merck Veterinary Manual. ## Further Reading - [American Veterinary Medical Association: First Aid Tips for Pet Owners](https://www.avma.org/resources-tools/pet-owners/emergencycare/first-aid-tips-pet-owners) - [Merck Veterinary Manual: Guinea Pigs](https://www.merckvetmanual.com/all-other-pets/guinea-pigs)