Rabbit, Guinea Pig, and Chinchilla Drooling or Not Eating: Dental Malocclusion (Overgrown Teeth) Causes and When to See a Vet

Rabbits, guinea pigs, and chinchillas all have teeth — not just their incisors, but their cheek teeth (molars) too — that keep growing throughout their lives. Normally, chewing wears the teeth down against each other and keeps their length in check, but when wear falls behind for any reason, the teeth can grow too long or come in crooked — a condition called dental malocclusion. Incisor malocclusion is visible from the outside, but the cheek teeth further back actually cause more problems, and issues there are often hard to notice just by looking.

Why it happens

The most common cause is not enough fiber (hay) in the diet. Chewing tough hay for long periods is what wears the cheek teeth down normally — a diet based mostly on pellets or soft vegetables means less chewing time and effort, so the teeth just keep growing longer. Other causes include:

Genetic predisposition: Chinchillas and some rabbit breeds bred for a shortened skull often have an upper and lower jaw that don't line up well, putting them at higher risk of malocclusion from birth.
Traumatic malocclusion: If an incisor breaks or is knocked out from a fall or chewing on a cage, the opposing tooth loses the tooth it normally wears against and can grow longer than it should.
Calcium metabolism problems: Especially in guinea pigs, an imbalance in vitamin D or calcium can weaken the bone structure that supports the teeth, which can lead to malocclusion.

What to check

Drooling ("slobbers"): The fur under the chin or inside the front legs looks constantly wet or matted.
Selective eating: Avoiding hay or hard vegetables and only picking out soft food like pellets. It's also common to see them take food into their mouth, fail to chew it, and drop it.
Weight loss: Chewing hurts, so they simply eat less overall.
Watery eyes (rabbits): When the roots of the upper cheek teeth overgrow, they can compress the tear duct and cause constant tearing.
A hard lump on the cheek or jaw: If a cheek tooth root pushes through the bone or an abscess forms, the side of the face or lower jaw can look hard and swollen.

What to check at home

Check the fur under the chin and inside the front legs: Feel with your hand for dampness or matting.
Watch how they eat: Offer hay or hard vegetables they normally like and watch whether they actually chew and swallow, or take food into their mouth and spit it out.
Check for weight change: Weigh them on a scale if you can, to check whether they've lost weight over the past few days. Don't try to force their mouth open to inspect the teeth — it's hard to see anything accurately without sedation, and it can cause stress or injury instead.

When to see a vet

Malocclusion itself is usually a slowly progressing, chronic problem — if there's only drooling or a bit of picky eating, it's not something that needs an immediate emergency-room trip. That said, it won't get better on its own and keeps getting worse if left alone, so it's safer to schedule a visit with a vet who treats exotic pets within the next few days.

There is an exception, though. Rabbits and guinea pigs are animals where stopping eating entirely because chewing hurts can lead to GI stasis (gut motility grinding to a halt) within hours. If they've gone completely without eating for 24 hours or more, or the cheek or jaw area feels hard and swollen or you see pus, contact a vet right away.

Diagnosis usually involves a direct look inside the mouth with a dedicated otoscope under sedation or anesthesia, sometimes along with X-rays to check the condition of the tooth roots. The standard treatment is trimming (burring) down the overgrown teeth; if a root is severely deformed or an abscess has formed, extraction or further treatment may be needed. Malocclusion is often not something that's cured with a single trimming — periodic repeat treatment is common — and giving unlimited hay access day to day helps reduce recurrence. The exact treatment schedule and method is entirely up to the vet's judgment.

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Frequently Asked Questions

There's just a little drooling — do I need to go to the emergency room right now?

If drooling is the only symptom and they're still eating reasonably well, malocclusion is usually a slowly progressing chronic problem, so it's not something that needs an immediate emergency-room trip. That said, it won't get better on its own, so it's a good idea to schedule a visit with a vet who treats exotic pets within the next few days. On the other hand, if they've gone completely without eating for more than 24 hours, or the cheek or jaw area feels hard and swollen, that's a true emergency — contact a vet right away.

What should I check at home before going to the vet?

Check whether the fur under the chin or inside the front legs is wet with drool, whether they're chewing and swallowing hay or vegetables they normally like (or dropping them from their mouth instead), and whether they've lost weight recently (weigh them if you can). Don't try to force their mouth open to look at the teeth yourself — it's hard to check accurately without sedation and it can just cause stress.

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📄 Printable summary of this guide — Emergency checklist PDF