Mind & Body · Friday, 4 September 2026

01 Briefing what happened

Your cough and your sense of taste run on the same tiny gate, so the drug that quiets one blanks the other

Mind & Body 1 min 50 sources

A cough is the airway's alarm. In about one adult in ten it never switches off, and the first drug built to quiet the nerve behind it takes taste with it.

1 in 10

adults worldwide living with a cough that has lasted over eight weeks

up to three quarters of those caused by acid reflux never feel heartburn at all [2]

2.5% to 35%

the reported range for a dry cough on ACE inhibitor blood-pressure pills

the same drug blocks an enzyme that clears an irritant out of the airway, so the cough is the drug working [17]

39.4%

the drop in coughing on 5 mg of morphine twice a day, in people with scarred lungs

44 patients, and they had no proven treatment before this trial [14]

43.6%

of people with a chronic cough have had it for more than five years

in Bergen, Norway, the figure reached 70.7% [11]

The lead story — what happened

A cough is one movement in three parts: a deep breath in, a hard squeeze against a shut throat, then the throat snaps open and the air leaves fast. [1]
It guards the lungs. It clears food, drink, smoke and mucus out of a tube that has no other way to empty. [1][41]
Doctors call a cough chronic once it has lasted more than eight weeks. In children of fourteen and under the line is four weeks. [1]
About one adult in ten in the world has one. [2]
Many keep coughing long after the illness that started it has gone, because the reflex itself has become easier to set off. [8]
The nerves that carry the cough signal sit in the throat and airway and run to the brainstem. Touch is enough: a camera brushing the voice box set one woman coughing repeatedly. [8][36]
Those nerves carry a tiny gate called P2X3, which opens when a cell nearby leaks the fuel molecule ATP. [4]
The same gate sits on the nerves that carry taste, and on nerves that carry pain. [4]
So the first drug built to shut that gate, gefapixant, cut coughing in large trials and left many people unable to taste their food. [6]
The trade is now the main brake on the whole drug class. Reviews list taste loss as the reason a working treatment is hard to use. [3][6]
There is still no test that shows a stubborn cough is real. No blood marker, no scan, nothing to point at. [7]
Chemists are not trying to aim better. They are looking for a second doorway into the same gate, in the hope that cough closes and taste does not. [5][4]

Who is involved

Jacky Smith

a professor of lung medicine at the University of Manchester in England; she says cough syrups cannot touch the virus, only the tickle it causes [28]
Haleon

the company that paid for the 2025 review judging guaifenesin and dextromethorphan, the two commonest cough-syrup ingredients, to be effective [22]
The MUCOSA trial team

the researchers who tested an asthma antibody on stubborn cough; it stripped out the suspect cells and changed the coughing not at all [15]
Physiotherapists at Cambridge University Hospitals

an English public hospital; they teach people to hold a cough down by hand, with no drug involved [41]
The Mayo Clinic cough clinic

a US referral centre; of 56 patients labelled untreatable, 35 turned out to have a cause after all [48]

What is pushing on this

A reflex turned up too high High↑

people keep coughing after the cause has gone, and cannot suppress it [8]

Drugs that can only find the nerve Building→

the gate that carries cough also carries taste [4]

Proof that the cough is real Easing→

no blood marker or scan exists for a stubborn cough [7]

A shelf of medicine nobody has tested well High→

many over-the-counter cough remedies have not been shown to work [45]

How it unfolded

2021 A dataset of 2,109,430 people in north-west London finds 2% carry a chronic cough, and 31% of them have no other diagnosis at all [10]
2023 Morphine at 5 mg twice a day cuts coughing by 39.4% in people with scarred lungs, from 21.6 coughs an hour to 12.8 [14]
Recently An antibody that wipes out the suspected inflammatory cells leaves the cough exactly where it was, in 30 patients [15]
2026 Reviews describe stubborn cough as a nerve disorder in its own right, with no test to confirm it and no drug free of a serious trade [7][3]

Where this points

The next test is whether a second doorway into the same gate quiets a cough and leaves taste alone. Until then the treatment that works is the one people cannot bear. [5][3]

The rest of the day

40 more stories on this beat.

Each with its own sources. None of these is a link to the story above.

02
Acid reflux coughs without heartburn

Up to 75% of people whose cough comes from acid coming back up the gullet never feel heartburn or a sour taste. The signal runs by nerve, not by burn. [2]

Why it matters — It is the plainest example of a cause that shows up nowhere near where it starts.
03
The asthma antibody that did nothing

In a 30-patient trial, mepolizumab cut blood eosinophils, a type of inflammatory white cell, by 237.7 cells per microlitre and changed 24-hour coughing by +18.0%, which is nothing. [15]

Why it matters — The inflammation everyone suspected turned out not to be what was driving the cough.
04
Morphine for a cough nobody could treat

In 44 people with scarred lungs, 5 mg of controlled-release morphine twice a day cut daytime coughing by 39.4%. Nausea hit 14% and constipation 21%. [14]

Why it matters — An old, cheap drug beat everything designed for the job.
05
An opioid that causes coughing

Sufentanil, a strong painkiller given at the start of an operation, made 42.66% of patients cough. A different opioid given first brought that to 0%. [16]

Why it matters — One family of drugs both stops coughing and starts it, depending on which nerve it reaches first.
06
The blood-pressure pill that makes you cough

Between 2.5% and 35% of people on ACE inhibitors report a dry cough. The enzyme those drugs block also clears bradykinin, an irritant, out of the airway. [17]

Why it matters — Blocking the enzyme is the treatment and the cough at the same time.
07
The same pills can flatten taste

Cleveland Clinic, a US hospital group, lists a reduced or metallic taste among the less common effects of ACE inhibitors, alongside the dry cough. [18]

Why it matters — Cough and taste turn up together again, on a completely different drug.
08
Genes decide who gets the cough

Among 107 patients in the United Arab Emirates, those carrying one copy each of two versions of the ACE gene were 2.34 times more likely to cough on the drug. [19]

Why it matters — The same pill is a different drug depending on the body it lands in.
09
Swapping the drug is not free

Across 72,534 people in the UK and 255,806 in China, five-year deaths were 3.45% on ACE inhibitors and 3.04% on the newer alternative. [20]

Why it matters — Two large databases suggest the substitute is not simply the same drug without the cough.
10
Guinea pigs sort the syrups

Codeine, cloperastine and gefapixant all cut coughing in guinea pigs given citric acid. Dextromethorphan and levodropropizine, both sold widely, did not. [21]

Why it matters — Two of the most common ingredients in a cough bottle failed the simplest test there is.
11
Who paid for the review

A 2025 review concluding that guaifenesin and dextromethorphan work lists Haleon as its funder. The review reports a high placebo response across the studies it covers. [22]

Why it matters — The review reaching the favourable verdict was paid for from inside the industry it judges.
12
A dummy syrup quiets the brainstem

Sixteen healthy people inhaled capsaicin, the heat chemical in chilli. After a placebo they wanted to cough less, and the brainstem sites where airway nerves land went quieter. [9]

Why it matters — Belief reaches the reflex itself, not just the report of it.
13
The cough medicine that is a psychiatric drug

Dextromethorphan blocks the NMDA receptor and switches on the sigma-1 receptor. Paired with other drugs it is approved for depression and for uncontrollable crying. [23]

Why it matters — The ingredient in a cold remedy is doing several unrelated jobs at once.
14
And it is sold on the street

The US National Library of Medicine lists dextromethorphan overdose as a recognised emergency, and notes the drug is sold under street names. [24]

Why it matters — The same molecule is a supermarket purchase, a psychiatric medicine and a drug of abuse.
15
Tested again in Huntington's disease

Researchers in Texas assessed dextromethorphan combined with quinidine for irritability in Huntington's disease, an inherited condition that damages the brain. [25]

Why it matters — A cough ingredient keeps being tried on the brain, because that is where it acts.
16
Japan counts the cost of long prescriptions

Among 10,385 people with a cough of weeks or months, 42.7% were prescribed centrally acting cough drugs. Past 57 days, constipation odds rose 1.80 times and nausea 2.06. [26]

Why it matters — The gut pays for what the brainstem is given.
17
India tries codeine plus an antihistamine

A multi-centre study across Indian hospitals followed patients with a dry cough who had failed non-opioid remedies, and gave them codeine with triprolidine. [27]

Why it matters — Where new drugs are out of reach, the old opioid is still the fallback.
18
Own-brand syrup is as good as the expensive one

Jacky Smith, a lung specialist in Manchester, England, says syrups soothe the throat and cannot touch the virus, and cheaper supermarket versions work as well as branded ones. [28]

Why it matters — The active part is the coating, and coating is not proprietary.
19
Honey, and the warning attached to it

Cleveland Clinic describes honey as a reasonable option for a mild cough in adults and children over one, and warns it can cause infant botulism in babies under a year. [29]

Why it matters — The most-recommended home remedy carries an age limit most people have never heard.
20
The evidence on bee products is thin

A scoping review found 35 studies of honey, propolis and other bee products in children's infections, mostly small trials, and called the quality inconsistent. [30]

Why it matters — Widely used is not the same as well tested, in either direction.
21
Honey is not inert

A toxicology review catalogues the active compounds in honey, including ones that can be harmful, and calls the substance a liquid with a dark side. [31]

Why it matters — Natural does not mean nothing is happening.
22
Patients rate their own remedies highly

Of 1,012 patients surveyed in primary care, most rated home remedies effective: 77% for onion syrup for a cough, 94% for thyme inhalation for a cold. [32]

Why it matters — Illnesses that end on their own hand credit to whatever was taken last.
23
Zinc gets the same treatment

A review finds zinc supplements consistently reduce how often children get chest and throat infections. As a treatment during an acute infection the evidence is much weaker. [33]

Why it matters — Preventing an illness and shortening one are separate questions, and the same supplement answers only the first.
24
Polluted air can sensitise the reflex

Guinea pigs exposed to nitric oxide over a long period coughed far more readily at a chilli challenge. There was no airway inflammation to explain it. [34]

Why it matters — The nerve can be turned up without anything looking inflamed.
25
Psychogenic cough gets a new name

Researchers in Shanghai, China trace the shift from psychogenic cough to somatic cough syndrome. They note that neither term has ever had a clear definition or agreed diagnostic criteria. [35]

Why it matters — A label with no criteria behind it still decides how a patient is treated.
26
A cough traced to a swollen neck vein

A 62-year-old woman coughed daily for two years. Scans found a widened jugular vein. Carbamazepine, an anti-seizure drug, with codeine nearly stopped it. [37]

Why it matters — It shows the range of things that can press on an airway nerve.
27
The cough clinic that is mostly women

Of 231 patients at one cough clinic, 164 were women. Men were more often found to have a cough coming from the nose and throat, 75% against 53%, or sleep apnoea, 21% against 6%. [12]

Why it matters — Same symptom, different causes, split along a line nobody has explained.
28
The tests double around the diagnosis

In a north-west London dataset of 2,109,430 people, chest X-rays around a chronic cough diagnosis rose from 6,535 to 12,880 and lung function tests from 5,791 to 8,720. [10]

Why it matters — With no test for the condition, the system runs the tests it has.
29
Untreatable is often a label, not a fact

At the Mayo Clinic cough clinic, 56 patients were considered to have refractory cough. A records review later found a confirmed cause in 35 of them, or 62%. [48]

Why it matters — Most of the mystery was missing information, not missing biology.
30
What a cough costs a life

Of 113 Taiwanese patients reporting complications, 46.0% had chest pain and 23.0% had urinary incontinence. A third of everyone surveyed had disturbed sleep, and self-paid costs ran about 94 US dollars a month. [13]

Why it matters — The damage is mechanical as well as social, and it is paid for privately.
31
Coughing is not throat clearing

In 40 healthy people, voluntary throat clearing moved air far more weakly than either a voluntary cough or a reflex one. [40]

Why it matters — The two sound alike to a clinician and do different amounts of work.
32
Machines now count coughs

Acoustic software can log every cough a person makes, day after day, without recording speech. Trials have started using the count as an endpoint. [38]

Why it matters — A symptom that was only ever described can now be measured.
33
Children who cannot cough hard enough

In children with neuromuscular disorders, which weaken the muscles used to breathe, a cough is too weak to clear the airway, and chest infections follow. [42]

Why it matters — The reflex everyone wants quieted is the one they are missing.
34
Cough measured across four lung diseases

The COASESS study enrolled 303 patients at ten university hospitals. Those with asthma and lung scarring carried a heavier cough burden than those with COPD or bronchiectasis. [39]

Why it matters — The same symptom is not the same weight in every disease.
35
Learning to hold it down

An English NHS hospital publishes a cough-suppression programme taught by physiotherapists, built on exercises rather than any drug. [41]

Why it matters — For a reflex with no proven pill, training the reflex is what is left.
36
The airway talks to the brain constantly

A review maps the nerve circuits running from the airway to the brain, which set breathing, trigger coughing and shift mood. [43]

Why it matters — Coughing sits on the same wiring as feeling ill.
37
And the airway has its own microbes

A review argues the nose and lungs carry bacterial communities that signal to the brain, a route studied far less than the gut. [44]

Why it matters — The airway is being read as a sense organ, not just a pipe.
38
Your nose is doing work you never notice

The bony ridges inside the nose stir the incoming air into turbulence, which lets the nose filter and moisten it before it reaches the lungs. [50]

Why it matters — Most of what protects the airway happens before any reflex is needed.
39
A nerve block for the voice box

A 2024 review of stubborn cough describes injections that numb the superior laryngeal nerve, which serves the voice box, alongside behavioural therapy, as options now in use. [46]

Why it matters — If the fault is a nerve, the treatments start looking like nerve treatments.
40
Where the doctor works changes the prescription

Among 203 paediatricians surveyed in Turkiye, those in private practice were 2.72 times more likely to give medicine for a child's cough, and reached more often for herbal remedies. [47]

Why it matters — The same viral cough gets a different answer depending on who is paying.
41
The swap has a rare cost of its own

A 58-year-old man began the usual alternative to an ACE inhibitor and, six months later, his lips and face swelled. It settled only when the drug was stopped. [49]

Why it matters — The replacement chosen to avoid a cough carries a rarer problem of its own.

02 Lesson why it matters

A drug cannot be aimed at a purpose, only at a part

The body uses one part for several jobs, so a drug that finds the part changes every one of them.

The twist

A side effect is rarely the drug missing. Bodies reuse their parts, so it is usually the same hit landing in another room, where nobody was watching.

How it works

One part of the body is used for several jobs
A drug can find the part, but not the job
So it changes every job that part is in
We name the change we wanted the effect
And the rest side effects, by our wanting
Aiming better does not help; only a different part does

Where you've seen this

A shared key

one key opens the front door and the shed, so changing the lock changes both

A road built for lorries

the school run uses it too, and closing it for repairs empties the school

One person covering two counters

move them to clear the queue and the other counter shuts with them

The catch

Not every unwanted effect is joined to the wanted one. Some come from a part the drug was never meant to touch, and those can be designed out.

And the whole of it

Everybody near this is looking at one job of a part that has several. The chemist sees the airway nerve, the patient tastes dinner, the trial counts coughs, and none of those views contains the others.

03 Truth what's really going on

What is really going on

A stubborn cough is being reclassified from a symptom of something else into a nerve disorder in its own right, and the first drug built for that nerve works well enough to sell and ruins taste, so the race is now for a second doorway into the same tiny gate. [3][5][7]

Why it works on us — Almost every cough ends by itself within a few weeks, so whatever was taken last gets the credit, and a placebo in the laboratory quiets the brainstem as well as the complaint. [1][28][9]

Who gains

Makers of over-the-counter cough syrup — Almost every cough stops by itself within weeks, so a product taken during that time is credited with the recovery it did not cause. [1][28][45]
The sellers of guaifenesin and dextromethorphan — The 2025 review concluding that both work lists Haleon as its funder, in a field where a guinea-pig comparison found one of them did nothing. [21][22]
Whoever finds the second doorway into P2X3 — A drug that quiets cough without wrecking taste inherits a market of one adult in ten, already proven to respond. [2][5]
Private paediatric practice — Paediatricians in private practice in Turkiye were 2.72 times more likely to prescribe something for a child's viral cough than those in public hospitals. [47]
Sellers of honey, thyme and herbal remedies — Patients rate them effective at rates from 77% to 94%, which is what a self-limiting illness produces for anything taken during it. [30][32]

Who pays

People whose cough has lasted years — 43.6% have had it more than five years, and in Bergen, Norway, 70.7% have. There is no test to confirm what they have. [7][11]
Anyone offered the drug that works — Gefapixant cut coughing in large trials and left many people unable to taste food, which is why reviews list it as hard to use. [3][6]
Women — They are the majority of chronic cough patients in every dataset here, their causes differ from men's, and no treatment is built around either finding. [10][12][26]
People on ACE inhibitor blood-pressure pills — Between 2.5% and 35% get a dry cough, and the usual alternative carried a slightly higher five-year death rate across 328,340 people in two databases. [17][20]
Children with weak breathing muscles — They cannot cough hard enough to clear the airway, and get the chest infections the reflex exists to prevent. [42]

What nobody knows yet

Open questions from across today’s stories — ours included.

01

Whether cough and taste can be separated at all.

The same gate on the nerve carries both, and the only published route around it is a different pocket on the same protein, tested in the laboratory rather than in patients. [4][5]
02

How many people actually have a chronic cough.

The two figures in this edition do not agree. A review of global data says about one adult in ten; Chinese insurance claims across nine cities give 8.88%; a UK dataset of 2,109,430 people records 2%, which is how many were coded, not how many coughed. [2][3][10]
03

Why most patients at cough clinics are women.

The pattern holds in the UK, Japan, Taiwan and single-clinic series, and no mechanism has been shown. The causes found also differ by sex, which nobody has explained either. [10][12][13][26]
04

Whether the common ingredients in cough syrup do anything.

In guinea pigs, dextromethorphan and levodropropizine did not reduce coughing at all, while codeine did. The human review that says otherwise was funded by a company that sells them and reports a high placebo response. [21][22]
05

What a stubborn cough looks like from the outside.

There is no blood marker, no scan and no agreed measure. Patients spend years being investigated before the label is applied, and at one referral clinic 62% of those labelled untreatable were later found to have a cause. [7][48]
06

How much of the burden is never counted.

The costs recorded are chest X-rays, lung tests and prescriptions. The incontinence in 23% of Taiwanese patients with complications, the broken sleep in a third of those surveyed, and about 94 US dollars a month paid privately appear in no health budget. [10][13]
07

Whether long courses of cough drugs are safe.

Japanese claims data links prescriptions beyond 57 days with higher odds of constipation and nausea, but the sickest patients get the longest courses, so cause and effect cannot be untangled. [26]
08

What the airway's own bacteria are doing to the reflex.

Researchers argue the nose and lungs signal to the brain the way the gut does. Almost nothing has been measured, and the comparison is a proposal, not a finding. [44]

04 Hope carry this

People with scarred lungs had no proven treatment for the cough that comes with it. In a trial of 44 of them, five milligrams of morphine twice a day cut their coughing from about 22 times an hour to 13.