A ranula is a soft, dome-shaped, bluish swelling that forms on the floor of the mouth under the tongue when a saliva gland leaks or becomes blocked. The name comes from the Latin word for frog, because the swollen, translucent bump can resemble a frog belly. It is almost always harmless, usually painless, and sits to one side under the tongue. Most ranulas come from the sublingual gland, and understanding why they form makes the treatment options much clearer.
Key takeaways
- A ranula is a mucus-filled swelling under the tongue from a leaking or blocked sublingual saliva gland.
- It is typically soft, bluish, painless, and on one side of the floor of the mouth.
- A simple ranula stays under the tongue, while a plunging ranula dips down into the neck.
- Small ones sometimes settle, but many need the sublingual gland removed to stop them returning.
- Removing just the swelling without addressing the gland often leads to it coming back.
Why a ranula forms
The sublingual gland sits in the floor of the mouth and constantly produces saliva. If its tiny duct is damaged or blocked, saliva escapes into the surrounding tissue and collects in a pocket, forming the swelling. Unlike a true cyst, a common ranula has no proper lining, it is simply a pool of trapped mucus, which is why it can wax and wane in size. Minor trauma to the floor of the mouth, such as a knock or a dental procedure, is a recognised trigger, though many appear without any obvious cause.
This mechanism is the same one behind a mucocele on the lip, just in a different gland and a larger scale. Our guide to a mucocele on the lip explains the smaller version that often appears after biting the lip.
The two types
| Type | Where it sits | Typical appearance |
|---|---|---|
| Simple (oral) ranula | Above the floor-of-mouth muscle, under the tongue | Soft bluish dome, often translucent |
| Plunging (cervical) ranula | Dips below the muscle into the neck | Neck swelling, sometimes with little visible in the mouth |
The plunging type matters because it can present as a soft swelling in the neck, which needs imaging to sort out from other neck lumps. This is one reason any persistent swelling under the tongue or in the neck should be assessed rather than watched indefinitely.
What a ranula feels like
A simple ranula is usually painless and slowly enlarges over weeks. If it grows large it can push the tongue up, make speaking or eating awkward, and occasionally get in the way of the bite. Some ranulas rupture on their own, release their fluid, deflate, and then slowly refill, which is a very characteristic history. A ranula that becomes red, hot, and painful may be infected and needs prompt care, along the lines set out in our guide to facial swelling and spreading infection.
How a ranula is treated
Treatment depends on size and type. A small, first-time ranula is sometimes watched to see whether it settles, but many persist or refill. The options are:
- Observation. A small, symptom-free ranula may be monitored for a short time in case it resolves.
- Marsupialisation. A minor procedure that opens the pocket and stitches its edge to allow drainage. It is simpler but has a higher chance of the ranula returning.
- Removing the sublingual gland. Because the gland is the source of the leaking saliva, removing it is the most reliable way to stop the ranula coming back, and it is often the recommended definitive treatment.
- Managing a plunging ranula. These usually need the gland removed as well, sometimes with drainage of the neck component, and imaging first to plan the surgery.
General cost guide
Costs depend on whether the ranula is watched, drained, or the gland is removed, and whether care is provided by a dentist or a specialist. The figures below are general Australian market ranges to help you plan, not a quote, and Lumi Dental does not list its own prices here.
| Service | General market range (AUD) |
|---|---|
| Examination and consultation | $60 to $130 |
| Imaging for a plunging ranula | $100 to $400 |
| Surgical removal of the sublingual gland | Varies, usually specialist referral |
If you have a swelling under your tongue that will not settle, the team at Lumi Dental can assess it and arrange the right care with a written plan. See the current deals page to book.
Frequently asked questions
Is a ranula dangerous?
A ranula itself is benign and not a cancer. The main issues are its size, the nuisance of it refilling, and the small chance of infection. A plunging ranula in the neck needs proper assessment to confirm what it is.
Will a ranula go away on its own?
Some small ranulas settle, and many rupture and deflate temporarily, but they commonly refill because the underlying gland keeps leaking. Persistent ones usually need treatment.
Why does removing the gland work better than draining it?
Draining or opening the pocket does not stop the sublingual gland leaking saliva, so the swelling often returns. Removing the source gland addresses the cause, which is why it has the lowest recurrence.
Is a ranula the same as a salivary stone?
No. A ranula is trapped mucus from a leaking gland. A salivary stone is a calcified blockage that causes mealtime swelling. Our guide to salivary gland stones explains that different problem.
Can children get a ranula?
Yes. Ranulas can occur at any age, including in children and newborns. Any persistent swelling under a child tongue should be reviewed by a dentist or doctor.
The takeaway
A ranula is a benign, mostly painless swelling under the tongue caused by a leaking saliva gland. Small ones may be watched, but persistent or plunging ranulas usually need treatment, and removing the source gland is the most reliable fix. If you have a soft swelling under your tongue, the team at Lumi Dental can help. Visit our current deals page to book.
This article is general information and is not a substitute for an individual dental or medical assessment.
