Pharyngitis

A pre-anaesthesia licorice gargle roughly halved post-operative/post-extubation sore throat versus sugar-water in a double-blind RCT (n=236) ^{11Reference 11Ruetzler K et al. · 2013RCTA randomised, double-blind comparison of licorice versus sugar-water gargle for prevention of postoperative sore throat and postextubation coughingView study →}, replicated in further gargle RCTs ^{12,13Reference 12Agarwal A et al. · 2009RCTEfficacy of licorice gargle for attenuating postoperative sore throat — randomised single-blindView study →Reference 13Honarmand A et al. · 2016RCTEfficacy of different doses of liquorice gargling for attenuating postoperative sore throat and cough after tracheal intubation — randomisedView study →} and ranked effective in a Bayesian network meta-analysis ^{14Reference 14Singh NP et al. · 2020Meta-analysisEfficacy of topical agents for prevention of postoperative sore throat after single-lumen intubation: a Bayesian network meta-analysisView study →}.

The evidence is for a specific entity — mechanical post-intubation sore throat prevented by a pre-procedure gargle — not infectious pharyngitis; swallowed licorice tea is not shown to help an ordinary sore throat, and glycyrrhizin carries a pseudo-aldosteronism (blood-pressure/potassium) caveat.

A double-blind, placebo-controlled RCT (n=286) found a 15% sage-extract throat spray significantly reduced pharyngitis pain within two hours of first use ^{23Reference 23Hubbert et al. · 2006RCTEfficacy and tolerability of a spray with Salvia officinalis in the treatment of acute pharyngitis — a randomised, double-blind, placebo-controlled studyView study →}; an echinacea/sage spray matched a chlorhexidine/lidocaine spray in a comparator RCT ^{24Reference 24Schapowal et al. · 2009RCTEchinacea/sage or chlorhexidine/lidocaine for treating acute sore throats: a randomised double-blind trialView study →}, and an observational lozenge study reported reduced throat pain and lower oropharyngeal viral load ^{25Reference 25Weishaupt et al. · 2023Clinical trialReduction of viral load in patients with acute sore throats: results from an observational clinical trial with echinacea/salvia lozengesView study →}.

Effects are local (spray/gargle/lozenge) and several trials combine sage with echinacea, so sage’s independent contribution and any benefit from oral dosing remain unclear.

A 2023 RCT (n=60) of a topical andrographis throat spray in acute viral pharyngitis reported significant symptom relief versus a chamomile-spray control ^{1Reference 1Okonogi et al. · 2023RCTEfficacy of Andrographis paniculata spray in acute pharyngitis: a randomized controlled trial — RCTView study →}, and meta-analyses of standardized-extract trials in upper-respiratory infection report improvement in sore throat ^{2Reference 2Hu et al. · 2017Meta-analysisAndrographis paniculata for symptomatic relief of acute respiratory tract infections in adults and children: a systematic review and meta-analysis — systematic reviewView study →}. Pharyngitis-specific data are a single small spray trial; oral evidence is for standardized andrographolide extracts (often combination products), not bitter teas, and andrographis is avoided in pregnancy.

Marshmallow root/leaf mucilage forms a bioadhesive film that physically soothes inflamed pharyngeal mucosa; a randomized active-controlled trial of an Althaea-honey throat spray reported relief in sore throat ^{15Reference 15Roventa et al. · 2023RCTEffectiveness and tolerability of Ectoin mouth and throat spray Althaea honey (ERS09) for sore throat — randomised, active-controlled trialView study →}, and a combination extract containing marshmallow root (BNO 1030) reduced symptoms in paediatric acute non-bacterial tonsillitis ^{16Reference 16Popovych et al. · 2019RCTRandomized, open-label, multicenter comparative study of BNO 1030 extract (containing marshmallow root) in acute non-bacterial tonsillitis in children — randomised (combination product)View study →}. Both are spray/combination products, so marshmallow’s independent effect is unquantified and no monotherapy trial exists.

In Traditional Chinese Medicine burdock seed (Niu Bang Zi) is a named remedy to “disperse wind-heat and benefit the throat,” used for sore throat, cough and fever; burdock root/leaf extracts inhibit oral organisms in vitro ^{3,4Reference 3Pereira et al. · 2005In vitroAntimicrobial activity of Arctium lappa constituents against microorganisms commonly found in endodontic infections — in vitroView study →Reference 4Gentil et al. · 2006In vitroIn vitro evaluation of the antibacterial activity of Arctium lappa as a phytotherapeutic agent used in intracanal dressings — in vitroView study →}. The throat indication is traditional with only bench-level antimicrobial support — no clinical trial.

Elder is used in Western herbal medicine for sore throats (flower or berry preparations), and its best evidence is for shortening colds and influenza — illnesses that commonly include sore throat — from small RCTs tempered by one well-powered null trial ^{5,6,7,8,9Reference 5Zakay-Rones et al. · 2004RCTRandomized study of the efficacy and safety of oral elderberry extract in the treatment of influenza A and B virus infections — randomized controlled trialView study →Reference 6Zakay-Rones et al. · 1995RCTInhibition of several strains of influenza virus in vitro and reduction of symptoms by an elderberry extract during an outbreak of influenza B Panama — placebo-controlled, in vitroView study →Reference 7Tiralongo et al. · 2016RCTElderberry supplementation reduces cold duration and symptoms in air-travellers: a randomised, double-blind placebo-controlled clinical trial — RCTView study →Reference 8Hawkins et al. · 2019Meta-analysisBlack elderberry (Sambucus nigra) supplementation effectively treats upper respiratory symptoms: a meta-analysis of randomized, controlled clinical trials — meta-analysisView study →Reference 9Macknin et al. · 2020RCTElderberry extract outpatient influenza treatment for emergency room patients ages 5 and above: a randomized, double-blind, placebo-controlled trial — RCTView study →}; a standardized berry extract also inhibited respiratory bacteria and influenza virus in vitro ^{10Reference 10Krawitz et al. · 2011In vitroInhibitory activity of a standardized elderberry liquid extract against clinically-relevant human respiratory bacterial pathogens and influenza A and B viruses — in vitroView study →}. No trial measures sore throat as an endpoint, and raw plant must be cooked to neutralize its emetic lectins.

Myrrh resin is a classic Western astringent-antiseptic gargle for sore throat and inflamed gums, used as a diluted tincture or mouthwash; its topical mucosal-healing and anti-inflammatory action is borne out by oral/gingival trials ^{17Reference 17Mansour et al. · 2014RCTClinical efficacy of aloe vera- and myrrh-based oral mucoadhesive gels in minor recurrent aphthous stomatitis — randomised, double-blind, vehicle-controlled trialView study →} and its ethanolic extract inhibits oral pathogens in vitro ^{18Reference 18Abullais Saquib S et al. · 2021In vitroSynergistic antibacterial activity of herbal extracts with antibiotics on periodontitis bacteria — in vitroView study →}. No pharyngitis-specific trial exists, the active furanodienes barely extract into water (a high-alcohol tincture is needed), and it is contraindicated in pregnancy as a uterine stimulant.

Oregano tea, gargle or diluted oil is a traditional antimicrobial remedy for coughs, colds and sore throats; the carvacrol-rich oil disrupts bacterial membranes with broad in-vitro activity ^{19,20,21Reference 19Sakkas et al. · 2017ReviewAntimicrobial activity of basil, oregano, and thyme essential oils — reviewView study →Reference 20Burt · 2004In vitroEssential oils: their antibacterial properties and potential applications in foods — review; in vitro dataView study →Reference 21Xu et al. · 2008In vitroThe antibacterial mechanism of carvacrol and thymol against Escherichia coli — in vitroView study →}. There is no clinical trial for pharyngitis, the antibacterial effect is an oil-concentration phenomenon far above what a tea delivers, and the concentrated oil is a strong mucosal irritant that must be well diluted.

Plantain (Plantago) leaf has a long demulcent, mildly astringent reputation for sore throat and irritated respiratory mucosa; the strongest controlled data are for a multi-herb cough syrup (KalobaTUSS) rather than plantain alone ^{22Reference 22Carnevali I et al. · 2021RCTEfficacy and safety of the syrup “KalobaTUSS®” as a treatment for cough in children: a randomized, double-blind, placebo-controlled trialView study →}. The sore-throat use rests on tradition and its mucilage mechanism, not a dedicated trial.

Slippery elm inner bark is an official demulcent and common throat-lozenge ingredient; its ~7% mucilage hydrates into a viscous gel that coats and soothes the pharyngeal mucosa ^{26Reference 26Watts et al. · 2012Slippery elm, its biochemistry, and use as a complementary and alternative treatment for laryngeal irritationView study →}. The throat use is entirely mechanism-and-tradition — no controlled or observational clinical data — and the mucilage does not dissolve in alcohol, so a tincture is the wrong form (powder or decoction only).

Thyme is a traditional antiseptic gargle and steam-inhalation for sore throat and respiratory catarrh, its phenols thymol and carvacrol showing broad membrane-disrupting antibacterial activity in vitro ^{27Reference 27Nabavi et al. · 2015ReviewPlants belonging to the genus Thymus as antibacterial agents: from farm to pharmacy — reviewView study →}, with tannins contributing to the throat use ^{27Reference 27Nabavi et al. · 2015ReviewPlants belonging to the genus Thymus as antibacterial agents: from farm to pharmacy — reviewView study →}. No controlled trial tests thyme for pharyngitis; the antimicrobial data are at essential-oil concentrations far above what a gargle delivers, and the neat oil is a mucosal irritant.

Usnea tincture and gargle are a traditional antimicrobial remedy for sore throat, backed by replicated in-vitro activity of usnic acid against Gram-positive bacteria ^{29,30,31Reference 29Cansaran et al. · 2006In vitroIdentification and quantitation of usnic acid from Usnea species of Anatolia and antimicrobial activity — in vitroView study →Reference 30Tozatti et al. · 2016In vitroActivity of the lichen Usnea steineri and its major metabolites against Gram-positive, multidrug-resistant bacteria — in vitroView study →Reference 31Pompilio et al. · 2016In vitroAntibacterial and antibiofilm mechanisms of usnic acid against methicillin-resistant Staphylococcus aureus — in vitroView study →} but no human trial. Concentrated internal usnic acid is hepatotoxic (documented liver failure), so use is short-term topical/gargle, and an alcohol extract is preferred over a tea.