Bumps under the tongue are usually caused by blocked salivary glands, minor injuries, or cysts that form when saliva gets trapped in the tissue. Most are harmless and resolve on their own, though some require treatment. The floor of your mouth contains a dense network of salivary glands, ducts, and delicate tissue that makes it a common spot for small lumps to develop.
Salivary Gland Cysts (Ranulas)
The most distinctive bump that forms under the tongue is a ranula, a fluid-filled cyst that develops when a salivary duct gets damaged or blocked. You have a pair of sublingual glands sitting just below either side of your tongue, each about the size of an almond. These glands constantly produce saliva and drain it through tiny ducts into your mouth. When one of those ducts is disrupted by injury, a mucus plug, or inflammation, saliva spills into the surrounding soft tissue and pools into a visible swelling.
Ranulas typically appear as soft, bluish or translucent bumps on the floor of the mouth. They’re painless in most cases but can grow large enough to push your tongue upward and interfere with eating or speaking. A less common type, called a plunging ranula, extends deeper along the tissue planes of the neck and can cause visible swelling below the jawline.
Treatment depends on size. Small ranulas sometimes drain on their own. For persistent ones, a procedure called marsupialization opens the cyst and allows it to drain continuously while the tissue heals. In one study, all 20 patients saw their ranulas resolve after this approach, though five experienced a recurrence. When cysts keep coming back, surgical removal of the cyst along with the sublingual gland is the more definitive option.
Mucoceles From Minor Gland Injury
Mucoceles are smaller cousins of ranulas. They form when a minor salivary gland (you have hundreds of these tiny glands lining your mouth) gets nicked or irritated, causing mucus to leak into the tissue. Biting the inside of your mouth, burning it on hot food, or even repeated friction from a rough tooth edge can trigger one. They show up as small, round, fluid-filled bumps that are usually painless and soft to the touch.
Most mucoceles burst on their own within a few days to weeks. If one keeps refilling, a dentist can remove it with a simple in-office procedure. They’re one of the most common oral soft tissue lesions and almost never a cause for concern.
Salivary Gland Stones
Salivary stones, or sialoliths, are hardened mineral deposits that form inside a salivary duct and block the flow of saliva. When this happens under the tongue, you may feel a firm, painful lump along the floor of your mouth. The hallmark symptom is pain and swelling that flares up when you eat, since chewing triggers saliva production that has nowhere to go. This discomfort typically lasts one to two hours after a meal, then eases until you eat again.
Some stones are tiny, no bigger than a pencil point, and cause no symptoms at all. Larger ones, around the size of a pea, can trigger sudden intense pain, a bitter taste, difficulty swallowing, or swelling under the jaw. If a stone blocks the duct long enough, the trapped saliva can become infected, causing redness, inflammation, and sometimes pus draining from the duct opening.
Small stones often pass on their own with hydration, warm compresses, and gentle massage of the area. Sucking on sour candy can stimulate saliva flow and help push the stone out. Larger or stubborn stones may need to be removed by a specialist, sometimes through dilation of the duct opening or a minor surgical procedure.
Canker Sores
Canker sores (aphthous ulcers) frequently appear on the floor of the mouth and can feel like a raised bump before they open into a shallow, painful crater. They’re typically small, under one centimeter across, and may appear solo or in clusters. Unlike cold sores, canker sores aren’t contagious and aren’t caused by a virus. Triggers include stress, minor mouth injuries, acidic foods, and hormonal shifts.
Most canker sores heal within one to two weeks without treatment. Over-the-counter numbing gels or antiseptic rinses can reduce discomfort in the meantime. If you regularly get large or persistent canker sores, that pattern is worth mentioning to a doctor, as it can sometimes signal nutritional deficiencies or an immune system issue.
Oral Papillomas
Oral papillomas are benign, wart-like growths caused by chronic infection with certain strains of human papillomavirus (HPV). They can appear on the lips, tongue, gums, tonsils, or the floor of the mouth. These bumps are usually pink or white, have a slightly rough or textured surface, and vary in size. They’re painless and slow-growing.
A single papilloma is not cancerous and doesn’t typically become cancerous, but it won’t go away on its own. Removal is straightforward, usually done in a single office visit, and recurrence is uncommon once the growth is fully excised.
Signs That Need Medical Attention
Most bumps under the tongue are benign, but a few features set apart the ones worth getting checked. The widely used guideline is the two-week rule: any sore, lump, or growth in your mouth that hasn’t healed or started shrinking within two weeks should be evaluated. Mouth cancer, while less common, can appear on the floor of the mouth as a persistent sore that won’t heal, a white or reddish patch, or a firm growth that gradually enlarges.
Other warning signs include pain that spreads to your ear, difficulty or pain when swallowing, loose teeth without obvious cause, and numbness in part of your tongue or lip. These symptoms don’t automatically mean cancer, but they do overlap with conditions that benefit from early diagnosis. A provider will typically start with a physical exam and, if needed, order imaging or a fine-needle biopsy to determine what the bump is made of and whether it needs further treatment.