Common Illnesses

Like other animals, hamsters can get sick from time to time and may require vet care. When you adopt a hamster you are agreeing to care for all its needs, including providing veterinary care when needed. Please ensure you are budgeting these costs into your ownership of a hamster. The following will discuss some common ailments, illnesses, and common injuries. If in doubt, go to the vet; remember that hamsters can hide pain or illness and it’s better to have them seen than to wait.

Wet Tail, aka Proliferative Ileitis

The most well known illness that afflicts hamsters is something called wet tail. There are a lot of misconceptions out there. There are lots of different diarrheal disease but they all have one thing in common: diarrhea - wet mushy liquid poop. If your hamster doesn’t have diarrhea it doesn’t have wet tail. If your hamster peed on itself and now has a wet tail it doesn’t have “wet tail.” If your hamster spilled water on itself and now has a wet tail it also doesn’t have “wet tail.” If your hamster is lethargic and dehydrated but has no diarrhea it is sick and you should take it to a vet, but if there’s no diarrhea it is NOT wet tail.

So what is wet tail? Well there are multiple things that can cause diarrhea in hamsters. The easiest to fix is a simple upset stomach. Give it some oatmeal, keep it hydrated, and monitor it. Take it to the vet if things don’t get better right away.

The second possible cause of diarrhea is proliferative ileitis. This is way more serious and what people usually refer to when they are talking about “wet tail.” Here the culprit is the bacteria Lawsonia intracellularis, which is most likely to infect hamsters that are stressed. The symptoms include diarrhea, lethargy, dehydration, and weight loss. The only way to cure this is with immediate antibiotics and supportive care. Do not get the “Wet Tail” drops from the store. At best those drops will hide the symptoms for a bit until it is too late to get your hamster real help. This generally only infects young hamsters under 12 weeks and generally only syrian hamsters.

A third possible cause of diarrhea is called Tyzzer’s Disease. This is a digestive illness caused by the bacteria Clostridium piliforme. It can have many of the same signs as proliferative ileitis listed above. This is also an emergency and requires antibiotics and fluid replacement therapy. Go to a vet. This one is more likely to affect young, old, and immunocompromised hamsters, but any hamster can get it.

There are other causes of diarrhea like parasites, E.Coli infections, or even antibiotics. If you don’t know which is causing your hamster’s diarrhea go to a vet.


Only Russian Dwarf Hamsters are likely to develop diabetes, particularly Campbell’s dwarf hamsters and Hybrid hamsters. Other species of hamsters, like Chinese hamsters, may develop diabetes but they aren’t particularly likely to develop it.

Although there isn’t a lot of great research on diabetes in hamsters it seems that hamsters likely follow a similar pattern as humans with types of diabetes. In Type 1 diabetes the pancreas does not produce insulin and therefore the body is unable to use the glucose from the food you eat. When this happens the glucose builds up in the blood causing high blood sugar. If that high blood sugar isn’t treated it can damage eyes, kidneys, nerves, the heart, and even lead to death.

In Type 2 diabetes people generally are able to produce at least some of their own insulin. However, their pancreas may not be able to produce enough insulin or their body may be insulin resistant. This means that their body will not be able to efficiently use the glucose in their blood and therefore will end up with high blood sugar. Type 2 diabetes can sometimes be controlled with diet and exercise but this is not always the case. It seems likely that type 2 diabetes might also have a genetic component even if it can sometimes be caused by lifestyle.

Hamsters seem to be more affected by Type 1 diabetes, which seems to have a strong genetic link especially in Russians. The first signs of diabetes in hamsters are the same as for humans. These symptoms are called the 3 Ps of Diabetes: Polyuria (excessive peeing), Polydipsia (excessive drinking), and Polyphagia (excessive eating). You can test for diabetes with Keto-Diastix strips, which measure the Ketones and Glucose in the urine.

Diabetes in hamsters can be medically managed using insulin with the help of your vet. For more information on diabetes, how to treat it, please visit The Pipsqueakery.


Strokes occur when blood supply to the brain is interrupted or reduced. Strokes commonly afflict older hamsters but can happen in younger hamsters as well. The most telling sign of a stroke is weakness on one side of the body. A hamster may appear unbalanced or wobbly and have difficulty getting around. They may have some paralysis in parts of their bodies or a head tilt.

Many hamsters can successfully recover from a stroke. They may have lingering effects such as weakness on one side or a head tilt, but many recover with no ill effects. If you suspect your hamster is having a stroke, the first step is to remove objects that may harm your hamster - levels, wheel, or anything sharp. You’ll want to ensure body temperature is maintained. A heating pad will help If your hamster is having trouble staying warm.

There is very little a vet can do to help with a stroke except providing oxygen to help prevent any brain damage due to oxygen loss. If you are concerned, please have your hamster seen by a vet. They should always be your first line.

Congestive Heart Failure

Congestive Heart Failure (CHF) is usually seen in older hamsters. CHF causes the heart to weaken and slowing down, making it unable to pump efficiently. Symptoms include fatigue, decreased circulation to extremities (blue/pale/cold paws due to cyanosis, or deoxygenated blood), bloating due to excess fluid (edema) in abdomen, and increased respiration. Your veterinarian might recommend an X-Ray for diagnosis. Once CHF has been confirmed, you can manage the symptoms with diuretics, like Lasix.

Amyloidosis may also cause CHF-like symptoms. This is a buildup of protein in tissues which can enlarge organs. It also commonly affects the kidneys, which presents as protein in the urine, as it reduces the kidneys’ ability to filter proteins.

Renal Failure

Renal failure, or kidney failure, tends to affect older hamsters as their bodies begin to become less efficient. The kidneys become less efficient at filtering waste out of the blood stream. This can lead to increased fluid in the body (edema) which causes swelling in the abdomen. You may also see weight and hair loss, with increased urination and drinking.

Many Syrians have kidney failure at the end of their life. This is why it is so important to reduce their protein intake as they age. Hamsters should be fed 20% protein when pups, but after they hit a year it is recommended to lower it to 17-18%. At 18 months, further reduction should happen, with 15-16% being adequate for most hamsters. Some hamsters may benefit from a 14% protein diet in their senior years.


Hamsters can have seizures, which occur due to abnormal brain activity. Some reasons a hamster might have a seizure is low blood sugar (in diabetic hamsters), dehydration, shock, trauma, stroke, or even tumours. Seizures can look scary, where the hamster shakes violently and is unresponsive, or they can be just a very unresponsive hamster.

In the case of low blood sugar, administering glucose (sugar) as soon as possible is important. Fruit juice, or even sugar water, can be used. In other cases, it is recommended to follow up with your vet to discover the cause of the seizure.

In the moment, remove all harmful objects from your hamster and ensure they’re not in an area where they could fall or hurt themselves.


Like many animals, hamsters can get cancer. This can be seen in external or internal masses, or even discoloured skin. Not all masses will be malignant however. Discuss with your vet about options for surgical removal, or follow their guidelines about comfort care at home.


Torpor is similar to hibernation, where a hamster goes into an extreme state of inactivity, lowering both breathing rate and heart rate. In the wild, this is how hamsters survive the winter. However, in captivity many hamsters have lost the ability to successfully wake up from torpor.

Hamsters will go into torpor when it is cold, or food and water are scarce. The hamster will become inactive, unresponsive, and its body temperature will lower. The best way to help your hamster wake up from torpor is to warm it up. Once the hamster is warmer, face the hamster’s head downwards and run warm fruit juice or sugar water over the mouth. Continue until the hamster has revived.

Unfortunately, not all hamsters will recover from torpor, even with the best efforts. To avoid this, ensure your house is kept at a reasonable temperature, keep your hamster away from drafts, and always remember to feed and water your hamster.

Fungal Infections

Hamsters can get fungal infections like ringworm and candida (yeast). These usually manifest as hairless areas with flakey skin. Ringworm will resemble a circle pattern. These can affect any part of the animal and must be dealt with immediately.

Ringworm is very contagious and can be passed to humans, or from humans. Take your hamster to the vet and discuss getting an anti-fungal cream to treat it. Your vet will likely do a skin scrape to test what kind of fungus is present.


Mites are external parasites that survive off the blood of a host. Hamsters are commonly affected by two main types of mite; tropical rodent mites and demodex mites. Tropical Rodent Mites are visible to the naked eye and look like black pinheads. They move alarmingly fast, and like moist, warm places, like the groin and underarms of your hamsters. They are highly contagious and will hide in bedding or wood toys. Rodent mites will also bite humans, leaving mosquito bite-like welts. Demodex mites are always present on hamsters, but during times of stress can increase in numbers and cause problems.

Both species of mites can be successfully treated using a medication called Revolution (Selamectin) which you can get from your vet. Either the Puppy/Kitten or Cat formula is acceptable. A small drop on the back of the neck is all the hamster needs. This should be re-applied in three weeks. The cage should be cleaned thoroughly, with all wooden toys tossed out.

Ivermectin can be used to treat mites however is not recommended. Ivermectin is very easy to overdose on, and some strains of rodent mites are resistant to it. It does not kill all life stages, as Revolution does.

Cataracts and Blindness

Occasionally, hamsters will get white circles in their eyes as they get older. These are cataracts, which is the clouding of the lens of the eye. It creates difficulty seeing. Hamsters can also go blind without cataracts. In general, hamsters have very poor eyesight and rely heavily on their sense of smell and hearing. Going blind is not a problem for hamsters. Just ensure their cage is safe, with no levels, and do not rearrange it too much. Your hamster will navigate it just fine.