Gerbils are usually very healthy and strong animals, they rarely have health problems. But when getting older, some ailments might show up. Here I will discuss the most common problems, and will try to give some solutions for those various problems. Please be careful, and visit a vet if you have any doubts!

FITS
About 1 in every 5 gerbils is prone to epilepsy, resulting in fits when they are under stress. The fit for instance when they are handled, or suddenly get into a new environment. Such a fit can vary in severity, but usually lasts only a few seconds to a few minutes. The gerbil lays flat, the ears go flat, the nostrils twitch. When this occurs it is best to put the gerbil back in its cage, and let it get to itself again. Usually those fits get less frequent when the gerbils get older and get more used to new and sudden things in their environment. Although having epilepsy does not affect the gerbils life expectancy in any way, I would not recommend breeding with gerbils prone to have fits.

DIARRHEA
Diarrhea can be a serious problem, often occurring in young, just weaned gerbils. When noticed early enough, it can very well be treated with an oral antibiotic like chlortetracycline. When diarrhea is noticed, stop feeding your gerbils greens and fruits, and you might want to isolate the affected animals, for diarrhea easily spreads (via your hands, for instance) to your other gerbils.

RESPIRATORY INFECTIONS
Also an ailment most common in young gerbils. The gerbils get lethargic, breathing is labored and most obvious is the "clicking" sound they make while breathing. Quick treatment is required here. An antibiotic treatment with either Baytrill or chlortetracycline can be very effective.

SORE OR RED NOSE
This is rather common in gerbils, the nose can get bald, red, sore and look bloody. The mucous coming from the irritated nose is red, looking like blood. This complaint is usually caused by an allergy to the bedding. The aromatic oils in wooden shavings, especially cedar and pine irritate the gerbils. So when your gerbils show this problem, first thing to do is change the bedding material, aspen, corn cob or a paper based bedding are much better. If the nose is so bad irritated that there is also a bacterial infection, that won't clear fast enough, a topical antibiotic such as neosporin can be applied twice a day. This should clear up the infection within 5 days.

PARASITES
Gerbils can catch several parasites such as mites (very rare), blood lice or ringworm.
Mites can be treated by a vet or by applying commercially available powder, the cage and all items in it should be washed out with boiling hot water, mixed with 1/10th bleach. Wash everything thoroughly afterwards.
Blood lice are very small and red or brown in colour, they are often brought in by birds, or in the bedding which has been contaminated by birds (doves). Blood lice can also bite humans and other animals in the household. They can be treated with a bird spray.
Ringworm is also contagious for humans and is a fungus. It is recognized by regular circular hair loss. Your vet will be able to confirm the ringworm by looking at the bare spot in a fluorescent lamp. It can be treated with a lotion. Make sure to contaminate the cage, and wash your hands very well after handling the animals, if you suspect ringworm.

ACCIDENTS
Most common accident with gerbils is the loss of their tail. The gerbils tail is rather fragile, and when picked up by the tail, or handled roughly, the tail tuft or tail skin can come off. This will bleed heavily, and bare bone might be seen. The bone will dry out and fall off within a few days. Nothing special need to be done, I have never heard of a tail getting infected, it will always heal naturally. The gerbil will hardly notice the shorter tail, and will behave as any other gerbil does.
Off course gerbils can also break a limb. Usually such breaks heal naturally without any treatment. The limb should not be splint, as that can cause even more damage to the animal. Just make sure your gerbil can get to its water and food.
Another reason for injuries can be fights. Those can be very serious, and fighting gerbils might even kill each other. Split up the fighting couple, and make sure they are all eating and drinking normal. In that case, they will be OK shortly, the wounds will usually heal without infections. If the gerbil is cold and badly injured, veterinary help should be applied.

CANCER
Most often occurring in older males are scent gland tumours. They usually start as a sore, rough, scabby spot on the scent gland. Usually those tumours grow very slow, and the gerbils are not really bothered by them when in the first stage. When a scent gland tumour gets really big and the gerbil gets irritated by it, it can be successfully removed by a vet.

OVERGROWN TEETH
Again more common in older gerbils. This often occurs when one of the teeth has been broken off, the opposite tooth can then grow too long. Be aware of this problem, check the gerbils teeth regularly, and especially when they are loosing weight. Overgrown teeth can be easily clipped by a vet or by someone who has experience in doing this.