Health Problems

The main signs to look for include loss of appetite, weight loss, and behavioral problems, but you should also check for particular symptoms of the following health problems.


f a wound is not treated quickly then it may heal over before the infection has cleared, causing pus to form under the skin and create a lump known as an abscess. It can be difficult to distinguish an abscess from a tumor if the original wound was not spotted, although if a wound is visible on the lump then it is most likely an abscess. If your hamster is scratching in a particular area then it may be because of an abscess, so be sure to look for any swollen areas or redness in the skin.

Abscesses can also be caused by cheek pouch injuries, so if your hamster has swollen cheeks or its cheek pouches appear to be continuously full then this may be an indication of an abscess. In the event of an abscess developing you should take your hamster to a veterinarian for the pus to be drained and possible further treatment. If the abscess bursts beforehand then it is still important that you visit the vet as additional treatment may be necessary to clear the infection.

Abscesses can be prevented by cleaning any bites, scratches or other wounds with peroxide, and contacting your veterinarian as soon as an injury leads to infection. You can also prevent wound from occurring in the first place by acting to protect your hamster from injuries such as broken bones and cheek pouch injuries.


Individual hamsters may be allergic to certain items, often types of bedding or food, though some hamsters can be allergic to dust or cage cleaner. Symptoms of an allergy include sneezing, runny eyes, skin irritation, fur loss, wheezing and breathing problems. In most cases where you suspect an allergy you should be able to isolate and remove the cause of the allergic reaction, allowing your hamster to recover within a few days. If symptoms appear severe however, or if there are any breathing problems, then you should seek veterinary advice as soon as possible.

To determine the cause of an allergic reaction you will need to consider what has changed recently in your hamster’s environment or diet, or use trial and error to narrow down the possibilities if you are unsure. For example, replace bedding material with tissue paper, feed your hamster a plain diet for a few days, move the cage to a different room, or temporarily clean the cage with just water.

Bladder & Kidney Infections

Symptoms of bladder and kidney infections include excessive urinating and drinking, blood in the urine, squealing when urinating, and lethargy. With more severe infections there may also be significant weight loss.

If your hamster has these symptoms then you should keep it in a warm location and take it for veterinary treatment as soon as possible. You should also clean the cage more regularly as the extra urine will increase the chances of fungus growing and causing further infection. Recovery normally takes a few days following treatment, although more serious infections may not be curable.

You can help prevent bladder and kidney infections by feeding your hamster a healthy diet. In particular, you should avoid giving too many foods with a high fat content as fat reduces the acidity of the urine.

Broken Bones

Your hamster may fall and suffer a broken limb or tail. This can occur if you handle your hamster unsafely outside its cage, or if there are multiple levels in its cage with areas where your hamster could fall from. If your hamster has broken any bones it will become evident from limping or a bent tail.

Broken bones cannot be plastered and so must be left to heal naturally. However, if a bone breaks through the skin and becomes exposed then you should take your hamster to a veterinarian to prevent infection. Also, if your hamster is showing signs of shock, this should be treated straight away.

To allow bone to heal naturally you should keep your hamster alone in its own separate cage, preferably an aquarium or another solid-sided cage with only one level to prevent climbing. Any exercise wheel and climbing toys should be removed as exercise will hinder recovery. It is also advisable to feed your hamster calcium supplements, or simply some milk-soaked bread or high calcium dog biscuits.

Broken bones should heal within one or two weeks, although your hamster may be left with a permanent limp or a crooked tail. Therefore it is best to try to prevent such accidents happening in the first place.

You can help avoid dangerous falls by ensuring there are no unprotected areas in a multi-level cage where your hamster may fall from a height, and by buying a safe hamster wheel. You should also ensure that you always handle your pet at a low height and over a soft surface, such as your lap.

Cancer & Tumors

Hamsters can potentially develop both external and internal cancerous tumors. These are more common for older hamsters and females.

External tumors are normally noticeable as a hard lump that may grow significantly in a short space of time. It can be difficult to distinguish between an external tumor and an abscess, although a tumor will sometimes be accompanied by general poor condition such as lethargy, weight loss and fur loss. If in any doubt you should see veterinary advice as soon as possible as many external tumors can be successfully surgically removed if diagnosed and treated quickly.

Internal tumors are difficult to diagnose and so are not normally treated early enough for surgery to be successful.

Cheek Pouch Injuries

Hamsters have cheek pouches to carry food and bedding, but sometimes an object can get stuck in the lining of the pouch which can lead to an infection, while an infection can in turn cause an abscess. If you notice any persistent lumps in your hamster’s cheek or if your hamster seems to be unable to empty its cheek pouches then you should take it to a veterinarian. Recovery should be made within a few days following treatment.

You can reduce the chances of cheek pouch injuries occurring by not giving your hamster sticky foods such as candy, and by avoiding the use of fluffy bedding, straw, pieces of material, and wool.


Like humans, hamsters can suffer from colds which give them a runny nose and sneezing. As long as these are the only symptoms you can treat a cold by placing some extra bedding in the cage and placing it in a warm room of constant temperature. You should also protect a wire cage from drafts. Giving your hamster some lukewarm milk with some honey added can further speed up recovery. If treated early, a cold should clear in a few days.

However, if more severe symptoms occur, such as lethargy, loss of appetite, runny eyes, or breathing problems, then you should get advice from a veterinarian. More serious illnesses such as bronchitis or pneumonia could develop if a severe cold is not treated quickly.

You can help prevent colds occurring by keeping your hamster away from drafts if using a wire cage. Since hamsters can catch colds from humans, avoid handling your hamster where possible when you have a cold. Always wash your hands before handling your hamster or preparing its food, and make sure that you never bathe your hamster.


Constipation can occur due to a lack of water, too much dry food, or a stomach blockage. If your hamster is constipated you will notice a lack of droppings, or a smaller amount of droppings, in the cage, while any droppings that are there may be small and hard. Other symptoms include a loss of appetite and walking with a hunched back.

If your hamster is constipated then make sure it always has water available in its bottle and give it some fresh food with high moisture content such as seedless grapes, cucumber or apple. A drop of vegetable oil in its food can also help.

Your hamster should start to recover after a day. Otherwise, take it to a veterinarian to be treated.


Diarrhea is most commonly caused by a sudden change in diet, feeding too much fresh food, and feeding too much moist food. It is normally easy to treat, however it can also be a symptom of the far more serious condition wet tail. If you suspect that your hamster has wet tail you should take it to a veterinarian as soon as possible.

Diarrhea can be identified by droppings that are soft, watery, and a lighter color than normal, while there may also be wet and matted fur around the tail. Your hamster should appear healthy in all other respects though, whereas wet tail has more wide-ranging symptoms.

Diarrhea can usually be resolved by removing fresh food from your hamster’s diet, and only feeding hamster mix, until the diarrhea has cleared. At this point you can start to slowly reintroduce fresh food. Exceptions are arrowroot and raspberry bush leaves which can help recovery from diarrhea. You should keep a hamster warm if it has diarrhea, and make sure it has plenty of water to avoid dehydration.

If your hamster does not recover after 2 days, if the diarrhea gets worse, or if other symptoms occur then you should take your hamster to a vet immediately.

You can help prevent occurrence of diarrhea by only feeding your hamster fresh food as a treat once or twice a week, and by introducing any new foods gradually. A good quality hamster mix should provide your hamster with the nutritional health it needs.

Ear infections

The symptoms of an ear infection are similar to those of a stroke, except an ear infection is normally treatable by antibiotics so you should therefore contact a veterinarian. Your hamster will show poor balance and coordination, possibly falling over, and its head may hang to one side.

Fungal Infections

Fungal infections can be caused by damp and dirty housing, and include ringworm and aspergillis fungus. They can be easily prevented by cleaning the hamster cage thoroughly once a week and replacing leaking water bottles. You should also make sure the cage is well ventilated, although this can be a problem with enclosed plastic cages.

Ringworm is the most common fungal infection, and gives a hamster round bald patches of dry and crusty skin which the hamster may scratch. If your hamster has ringworm then you should isolate it in a separate cage from any other hamsters and take it to a veterinarian as soon as possible.

Ringworm is caused by fungus that grows when moisture gets trapped in bedding, so replacing bedding once a week should prevent this infection.

Aspergillis fungus is a less common but more serious fungal infection. Symptoms include lethargy, breathing problems, inflamed skin, diarrhea, and blood in urine. You will also notice a fungus growing in the area where your hamster urinates. The fungus will be white at first before becoming black, at which point it can infect your hamster. It can also develop on rotting food that has been left in the cage for far too long. If you notice the fungus or any of the symptoms in your hamster then you should clean the cage and seek veterinary treatment immediately as the infection can be fatal. Any other hamsters in or near the cage should also be treated as the infection is spread through the air.

Aspergillis fungus can be prevented by cleaning the hamster cage once a week and removing fresh food every two days.

Heat Stroke

Heat stroke can occur if your hamster is kept in hot conditions. A hamster with heat stroke will lie flat on the floor of its cage, have heavy breathing, and may shiver when you touch it.

To help your hamster recover you should move its cage into a cooler area where your pet can slowly cool down. If there have been no signs of recovery after a few minutes then try spraying your hamster with a fine mist of cool water, or gently running some cool water (but not cold) over its body, then dry it gently. If there is still no indication of improvement then you should seek advice from a veterinarian as soon as possible. You should ensure that your hamster has a supply of water in its bottle to avoid dehydration, while fresh food with high moisture content such as seedless grapes, cucumber or apple can also help.

You can avoid heat stroke by keeping your hamster’s cage away from direct sunlight and heaters. During warmer weather you should move the cage to a cooler part of the house.

Lung Infection

A lung infection can be caused by an allergy, a cold, pneumonia, or bronchitis. Symptoms include labored breathing, wheezing, shivering, chattering teeth, lack of appetite and weight loss. If your hamster displays these symptoms then you should seek immediate veterinary treatment.

You can reduce the chances of your hamster developing a lung infection by protecting your hamster from colds and treating any colds or allergic reactions quickly.

Overgrown Nails

The nails of Campbell’s Russian dwarf hamsters can grow quite long, but this is generally not a problem. However, if your hamster’s long nails are causing it to scratch itself when washing or are curling under its feet, then you should get the nails clipped. You can do this by yourself but you should ask someone else to hold your hamster and be careful not to cut too close to the paws.

To prevent nails from causing problems you can file them down if you notice they are starting to get long. This can be done by placing a tile upside down somewhere in the cage where your hamster will walk, such as by its water bottle, and by providing some wooden toys that your hamster can grip onto. Alternatively, you could line a box with some fairly smooth sandpaper and allow your hamster to run around it for a few minutes every evening.


Occasionally a hamster may suffer from shock, such as after injuring itself, although the cause will not always be known. If your hamster is in shock then it will typically seem fairly limp and lifeless, while it may also be shivering, breathing heavily and have a colder temperature.

Shock should be treated immediately by rubbing your hamster’s back gently to encourage blood circulation. Also make sure your hamster’s cage is in a dark, warm and quiet room. If your hamster does not recover within an hour then it may need veterinary treatment, while any broken bones or other injuries will also need to be treated. You can help prevent shock in the same way as preventing broken bones, by making sure its cage is safe and by handling it safely.

Skin Problems

Skin problems can be caused by fungal infection, allergy, mites or mange. Symptoms include fur loss, dry, flaky skin, persistent scratching and skin sensitivity. If you notice any of these symptoms in your hamster then inspect its skin for mites. These are sometimes visible as small specks moving on a hamster’s coat, and you may find it easier to view them in the dark using a flashlight. You should isolate your hamster in a separate cage away from other hamsters, and use an anti-mite spray that can be bought from a pet store. Make sure however that you shield your hamster’s eyes from the spray. You should also clean the cage, spray it thoroughly with the ant-mite spray and replace the bedding. Ensure that any hay is replaced with alternative bedding as hay can be infected with mites. You may need to repeat this a few times depending on the instructions given on the spray.

A mild case of mites should clear within two days. Otherwise you should take your hamster for veterinary treatment to avoid mange developing. Mange is a more serious skin infection that is caused by mites. Scratching becomes even more frequent and there is more obvious fur loss, while scabs may also appear. You should treat mange in the same way as mites, except that you should take your hamster to the vet immediately. You should also clean the cage with a pet safe disinfectant.

Teeth problems

Hamsters’ teeth grow continuously, but are designed to wear against each other evenly when gnawing. However, sometimes teeth will become overgrown, unmatched or crooked, which can cause problems with eating or teeth growing into the roof of the mouth or into the cheek pouch. Therefore if your hamster has teeth problems you should take it to a veterinarian. Most teeth problems can be resolved by clipping the teeth, so you may want to ask your vet to show you how to do this safely.

The main symptom of teeth problems is a loss of appetite. So check your hamster’s teeth it is eating less or losing weight. You can help prevent teeth problems occurring by providing your hamster with plenty of chew toys to gnaw at, while dog biscuits can also help grind teeth down.

Wet Tail

Wet tail is a very serious stress-related disease that can result in death just 24 to 48 hours following the appearance of symptoms. It is therefore highly important to get veterinary treatment as soon as possible. Do not rely solely on drugs bought from pet stores, and keep any hamsters that you think have wet tail in separate cages from other hamsters. Wet tail is most common in baby hamsters, particularly around the time of weaning when they are about 4 weeks old.

The main symptoms of wet tail are diarrhea and a wet tail matted with faeces. Other symptoms include a foul smell, lethargy, lack of appetite, and a hunched back when walking. Symptoms can start to appear after 7 days. The causes of wet tail are all stress related and include changes in the hamster’s environment, changes in diet, poor cage cleaning, too much handling and other interference, separation from mother or siblings, and death of a mate.

Fortunately, it is fairly easy to avoid these causes by taking good care of your hamster. You should properly prepare a suitable cage before it is brought home, allow it to settle in before interfering with it, feed it a good diet regularly and introduce new foods gradually, clean its cage regularly, and tame it for handling gradually