Bad Taste From a Ruptured Abscess: What It Means When Drainage Starts Naturally

The sequence is memorable. Several days of escalating, throbbing pain, a swollen face, sleep that never quite happens — and then, often overnight, a sudden foul salty taste and the pain largely gone.

The natural conclusion is that the body has dealt with it. That conclusion is understandable and it is wrong. What has happened is that pressure inside the abscess has finally forced an opening through the bone and gum, and pus is now draining into the mouth. The pressure has gone, which is why the pain has gone. The infection has not.

This article explains what has occurred, why the relief is temporary, and why this remains a situation that needs a dentist rather than a wait-and-see approach.

What exactly am I tasting?

Pus. It consists of dead white blood cells, bacteria, breakdown products of tissue and inflammatory fluid, and the bacteria involved in dental infections are largely anaerobic — they produce volatile sulphur compounds as they metabolise protein. When the abscess finds an exit through the gum, that material drains directly into the mouth, which produces the characteristic salty, metallic or foul taste. Many patients describe it appearing very suddenly, often on waking.

The source. Almost all periapical abscesses begin inside the tooth. Bacteria reach the pulp through deep tooth decay, a cracked tooth, a failing restoration or an injury. The pulp becomes inflamed and eventually dies. Once it is dead it has no blood supply, so the immune system cannot reach the bacteria inside the root canal system.

The immune response. Bacterial products exit through the opening at the root tip into the surrounding bone. There, the body can respond — neutrophils are recruited in large numbers, and as they engulf bacteria and die, pus accumulates. Bone at the root tip is resorbed as part of this process.

Pressure and rupture. Pus accumulating in a confined space within bone generates considerable pressure, which is why the pain of an acute abscess is so severe and so relentless. The collection eventually erodes through the thinnest available bone and tracks to the surface, forming a channel called a sinus tract. When that channel reaches the gum and opens, drainage begins and the pressure falls.

A gum abscess, arising from deep periodontal pockets rather than from inside the tooth, follows a different route but presents similarly.

Sudden bad taste. Usually the first thing noticed, often on waking.

Rapid pain relief. Frequently dramatic. This is purely mechanical — pressure on the nerve endings is relieved. It is not resolution.

Ongoing discharge. A small pimple-like swelling on the gum, sometimes yellowish or with a visible opening, that fills and empties. It may discharge intermittently for weeks or months.

Reduced swelling. Facial swelling generally subsides over a few days once drainage is established.

A tooth that feels normal again. The tooth may become entirely comfortable, which is precisely why so many people postpone treatment.

The reason is simple and worth stating plainly: the bacteria are inside the root canal system, and nothing that has happened has removed them.

• The pulp is dead, so there is no blood supply and no immune access to the canal

• Antibiotics circulating in the blood cannot reach the bacterial reservoir either

• The sinus tract acts as a relief valve, so the infection persists in a chronic, low-grade state

• Bone at the root tip continues to be lost, which may compromise the tooth and affect the bone level around neighbouring teeth

• The tract can close over at any point, at which case pressure rebuilds and the acute episode recurs — sometimes worse than the first

• Chronic drainage into the mouth maintains a persistent bad taste and odour

Our article on apical periodontitis and infection spreading into the jawbone explains the underlying process in more detail.

• Sudden salty, metallic or foul taste

• Marked reduction in pain

• A recurring pimple-like lesion on the gum near the affected tooth

• Persistent bad breath

• Intermittent discharge, sometimes noticed as a taste rather than seen

• Tenderness when the tooth is tapped, even if it no longer aches

• The tooth may darken in colour over time

• Occasional flare-ups of pain and swelling when drainage is obstructed

Seek urgent care the same day if you have facial swelling that is increasing, swelling involving the eye or beneath the jaw, fever, difficulty opening the mouth, or difficulty swallowing. Difficulty breathing or swallowing requires emergency medical attention rather than a dental appointment. Our emergency dentist page explains how to be seen quickly.

Arrange an appointment if:

• You have had a dental abscess that has burst or started discharging

• There is a recurring lesion on your gum

• You have a persistent bad taste from one area

• A tooth aches intermittently, or has stopped aching after a period of severe pain

• A tooth has changed colour

• You have completed a course of antibiotics and the tooth has not been definitively treated

That final point matters. Antibiotics prescribed to control swelling are a holding measure. If the tooth itself has not then been treated, the problem is unresolved regardless of how well you feel.

Assessment. Examination and radiographs establish which tooth is the source, how much bone has been lost, and whether the tooth is restorable. A gutta-percha point is sometimes placed into the sinus tract and radiographed to trace it back to the responsible tooth, since the opening is not always adjacent to it.

Drainage and infection control. Where a collection remains, it may be drained. This provides rapid relief but is not definitive treatment.

Root canal treatment. The primary option where the tooth is restorable. The canal system is accessed, cleaned mechanically and chemically to remove the bacterial reservoir, and sealed. Once the source is eliminated, the sinus tract typically closes within days to weeks and the bone at the root tip heals over months. The tooth is usually then restored with a crown, since a root-treated tooth is more prone to fracture.

Extraction. Where the tooth cannot be restored — extensive decay below the gum level, a vertical root fracture, or too little sound structure remaining. Replacement options such as a dental implant or a bridge would then be discussed, and ridge preservation may be considered at the time of removal.

Antibiotics. Appropriate where infection is spreading, where there is systemic involvement or significant facial swelling, or where drainage cannot be established. They are not a treatment for the abscess itself, and unnecessary prescribing contributes to antimicrobial resistance.

Follow-up. Healing is confirmed by radiographic review after several months. The tract closing and symptoms resolving is encouraging but is not proof that bone has healed.

• Brush twice daily with fluoride toothpaste and clean between the teeth every day

• Reduce how often you have sugar, not simply how much

• Attend routine check-ups with radiographs at the interval advised

• Keep hygiene appointments so gum pockets are monitored

• Have small cavities restored early with a white filling rather than waiting

• Do not ignore a tooth that hurt badly and then stopped

• Wear a night guard if you grind, since cracks are a common route of bacterial entry

• Rupture relieves pressure, which is why the pain stops — it does not clear the infection

• The bacterial source sits inside the root canal system where the immune system cannot reach

• A recurring pimple on the gum is a sinus tract and is a sign of ongoing infection

• The tract can close, causing the acute episode to recur

• Bone at the root tip continues to be lost while the infection persists

• Root canal treatment or extraction is needed to resolve it definitively

• Facial swelling, fever or difficulty swallowing require urgent care

The NHS page on dental abscess covers symptoms, urgency and treatment.

If your abscess has burst, the worst of the discomfort is probably behind you. The problem is not.

Drainage is the body doing the only thing it can do about a bacterial reservoir it cannot reach. Removing that reservoir requires treating the tooth, and doing so promptly gives the best prospect of keeping it.

To have the tooth assessed, arrange an appointment at 22 Wimpole St, London W1G 8GQ, or call 020 7183 0692.

Dental symptoms and treatment options should always be assessed individually during a clinical examination.

This article is for general educational information only and is not professional dental advice, diagnosis, or a treatment recommendation. Information here is general and cannot replace an in-person assessment by a qualified, GDC-registered dental professional. Symptoms, suitability, fees, timelines, and outcomes vary according to individual clinical circumstances. If you have pain, swelling, or other concerning symptoms, seek prompt professional dental care. Always request a written treatment plan and cost estimate before proceeding with treatment.

Written Date: 6 September 2026 Next Review Date: 6 September 2027