Metallic taste
The feeling of having held a coin in your mouth, or sucked on a rusty nail, is familiar to a great many people.
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Medicines commonly prescribed for Metallic taste
For informational purposes only. Always consult a doctor before taking any medication.
Dosage form: CAPSULE, 20 mgActive substance: omeprazoleManufacturer: Laboratorios Alter S.A.Prescription requiredDosage form: CAPSULE, 20 mgActive substance: omeprazoleManufacturer: Aristo Pharma Iberia S.L.Prescription requiredDosage form: CAPSULE, 40 mgActive substance: omeprazoleManufacturer: Meiji Pharma Spain S.A.Prescription required
The feeling of having held a coin in your mouth, or sucked on a rusty nail, is familiar to a great many people. Behind it there is usually something simple: a medicine started the day before, a bleeding gum, a blocked nose. In those cases the taste clears on its own once the cause does, and there is nothing to treat separately. But this complaint has another side to it: occasionally a taste of metal is the only thing a person notices while something serious is going on inside. Both situations are set out below — where to start looking for the cause, what you can sort out yourself, and when the taste is a reason not to put off seeing a doctor.
Where the taste of metal comes from
What we call taste is only partly produced by the tongue. The tongue tells sweet from salty, sour, bitter and the savoury taste of protein foods; all the remaining richness of flavour comes from smell, because odours rise from the mouth into the nose from the inside and the brain adds them to the signals from the tongue to make a single sensation. A fault in either channel therefore gives the same result: a persistent metallic undertone that water will not rinse away.
That leaves three different mechanisms. The first is that metal really is in the mouth. Its commonest source is blood, which is rich in iron: a single drop from an inflamed gum is enough to give the unmistakable taste. The second is that a substance reaches the saliva from within. Many medicines are partly cleared through saliva and are tasted regardless of the form in which they were given, which is why the taste appears after a tablet and after an injection alike. The third is that the signal itself is distorted: smell weakens after a cold, nerve pathways are irritated, and the brain reconstructs the picture wrongly.
The practical point is that the cause is not to be looked for in the mouth alone. If the teeth are sound and the gums are not bleeding, the next places to look are the list of medicines, the nose and general health.
Medicines are the commonest cause
If the taste started with a new medicine, then in nine cases out of ten the medicine is the reason. The clue is straightforward: try to recall what changed in your medicine cabinet a week or two before the taste appeared. Starting a course, increasing a dose or swapping one drug for another all count.
A metallic taste is described with many groups of medicines. It comes up most often with certain antibiotics and antiprotozoal drugs, antifungals, blood pressure medicines from the ACE inhibitor group, some diabetes treatments, lithium, sleeping tablets, iron and zinc supplements and inhalers. The list does not end there — hundreds of medicines can do it, and the exact answer is in the patient information leaflet or with your pharmacist.
The most important thing here is not to stop a prescribed medicine on your own. A metallic taste is unpleasant but harmless, whereas an interrupted course of antibiotics or an abandoned blood pressure tablet costs a great deal more. The right order is different: read the leaflet, ask a doctor or pharmacist whether the effect is known with your medicine, and decide together whether to wait until the course finishes, whether changing the time of the dose would help, or whether an alternative makes sense. As a rule the taste fades within a few days of finishing a course; with long-term treatment it may persist, but it gradually eases, because the brain grows used to it and stops picking it out.
Mouth, nose and sinuses
The second large group of causes is whatever is happening right next to the receptors.
- Gum disease. Inflamed gums, tartar, periodontitis: the gums bleed on brushing or even unprompted, and it is the blood that gives the taste of iron. This is the commonest local cause and also the easiest to deal with, through good cleaning and a dental appointment.
- Teeth and what has been put into them. Deep decay, inflammation around a root, an old leaking filling, a poorly fitting crown. A category of its own is different metals sharing one mouth: a crown of one alloy and a filling of another act in saliva like a weak battery, and the person notices a taste and a tingle. A dentist settles that by replacing the restoration.
- A dry mouth. Saliva constantly washes away and dilutes flavour compounds; when there is little of it, any taste is felt more sharply. Dryness comes from medicines, mouth breathing, dehydration, smoking, radiotherapy and some autoimmune conditions.
- Colds, sinusitis, nasal polyps. A blocked nose removes half of flavour, and what remains seems warped. After a viral infection smell sometimes returns neither at once nor completely: for a while familiar odours are read wrongly and food tastes of chemicals or metal. This usually recovers over weeks or months.
- Acid coming back up from the stomach. Heartburn, a sour or bitter taste in the morning, a lump in the throat, hoarseness — here the taste is only one of the signs, and it is the reflux that needs treating.
Pregnancy, deficiencies and cancer treatment
Pregnancy. A distorted sense of taste in the first trimester is commonplace: food changes flavour, favourite things become repellent, and metal sits in the mouth. The cause is the hormonal shift, it does no harm, and by mid-pregnancy the sensation usually goes on its own. Anything that strengthens flavour helps: sour drinks, sugar-free mint chewing gum, strongly flavoured food.
Deficiencies. Taste depends on several micronutrients. With low zinc, taste weakens and distorts; with vitamin B12 deficiency there is also a sore red tongue, weakness, pallor and pins and needles in the hands and feet; low iron brings pallor, breathlessness on exertion, brittle nails and sometimes an urge to chew ice. All of this shows on an ordinary blood test, and a deficiency is best corrected according to the result rather than blindly: too much zinc in itself interferes with the absorption of other minerals.
Chemotherapy and radiotherapy. Altered taste is one of the commonest companions of cancer treatment, particularly with radiotherapy to the head and neck, where both the taste buds and the salivary glands take the damage. It is an expected side effect, not a sign that things are getting worse. Taste comes back gradually once treatment ends, sometimes over several months. While it is altered, the thing that matters is not losing weight: raise it with the team looking after you, because during cancer treatment eating is part of the treatment.
When the taste is not a trifle
A taste of metal on its own calls for no alarm. What matters is what comes with it.
Call an ambulance on the single European number 112 if:
- the metallic taste comes with swelling of the lips, tongue or throat, a rash, wheezing, a feeling of not getting enough air or faintness — a severe allergic reaction can start this way, and it unfolds within minutes;
- alongside the taste the face suddenly droops, an arm or leg goes weak, speech becomes muddled, vision doubles, or the worst headache of your life comes on;
- breathing becomes difficult at rest and the face and legs are visibly swollen.
See a doctor the same day if:
- the metallic taste is joined by breathlessness, swelling of the face and legs, a sharp drop in how much urine you pass, stubborn itching of the skin, nausea and weakness. That combination occurs in kidney failure: when the kidneys stop clearing waste products, these build up in the blood, and a taste of metal is one of the early signs. This is the case in which the seemingly trivial complaint matters more than everything else on the list;
- taste and smell have gone together and are not coming back, especially if there is also numbness of the face, weakness in the limbs, unsteadiness on your feet or changes in memory;
- the taste began after a tick bite, all the more so with fever, aching or a red patch spreading around the bite;
- the taste followed a poisoning — spoiled food, mushrooms, fish from tropical seas (in that poisoning the metallic taste comes with a mix-up between hot and cold), household chemicals or fumes at work. Be particularly careful with jobs involving contact with lead, mercury and other heavy metals: there the taste goes together with abdominal pain, nausea, headache and irritability;
- there is an ulcer in the mouth that will not heal, a white or red patch, a tooth loosening for no reason, or a lump in the neck;
- the taste lasts longer than a few weeks and no cause for it is apparent.
What you can do yourself
- Get the mouth in order: brush twice a day, use floss or interdental brushes, clean the tongue gently, and book a scale and polish and a check-up. If the gums bleed, that is exactly where to start.
- Drink more plain water and do not let the mouth dry out. Sugar-free chewing gum and sour sweets get saliva flowing, and saliva dilutes the taste.
- Rinsing with warm water and a teaspoon of bicarbonate of soda per glass relieves the sensation for a while and does not dry the lining, unlike alcohol-based mouthwashes.
- Try foods with a strong flavour of their own: pickles, sour things, spices, ginger, citrus. Meat, which on this background tastes especially metallic to many people, goes down better marinated, or can be swapped for poultry, fish, eggs and pulses.
- Change metal cutlery and dishes for plastic, glass or wood — where the taste comes from treatment, this makes a noticeable difference.
- Have food and drink cold: cold food smells less, so the distortion of taste gets in the way less.
- Give up smoking: tobacco dulls and distorts taste in its own right, and does double harm to the gums.
- Write down when the taste started and what you were taking in those days, including vitamins, supplements and herbal products. With that list a doctor gets their bearings in a few minutes.
Online consultation
A metallic taste is precisely the kind of complaint in which nearly everything is settled by talking: there is usually nothing to examine, but the dates, the medicines and the accompanying symptoms can be matched up at a distance. The Oladoctor doctor will go through your medicine cabinet with you and say whether the effect is known with your drugs, whether it is worth waiting for the course to end, or whether it makes sense to discuss a change with whoever prescribed it. They will help you see where to look next — dentist, ear, nose and throat specialist or a blood test — advise which tests are worth doing in your case, and go through results you already have. And they will specifically check the thing this page was worth reading to the end for: whether the taste comes with breathlessness, swelling and a change in passing urine, because with that combination the conversation ends and you need to be seen in person the same day.
This material is for information only and does not replace medical advice.
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