• Nervous System: Extreme nervous and sensory irritability; heightened susceptibility to external impressions [Hering].
• Special Senses: Over-sensitive hearing and tactile sense; auditory hyperaesthesia a keynote [Clarke].
• Gastrointestinal Tract: Stomach and intestines irritated, with nausea, vomiting, and colic [Allen].
• Mucous Membranes: Irritative coryza and pharyngeal catarrh [Boericke].
• Respiration: Cough and dyspnoea from throat irritation [Hering].

• Resting in a warm room, shielded from sensory stimulation [Hering].
• Closing the eyes to avoid aggravation from light [Clarke].
• Warm drinks to soothe gastric and throat irritation [Allen].

• Noise, especially sudden or sharp sounds, which are almost unbearable [Hering].
• Touch or even the slightest jar, causing an oversensitive nervous reaction [Clarke].
• Cold, damp weather and draughts, which provoke catarrhal symptoms [Allen].
• Strong odours, which can induce faintness or nausea [Hughes].

Markedly nervous and excitable temperament, with acute sensory perception. Patients may feel mentally overstimulated by trivial impressions and become irritable or distressed [Hering]. There is inability to concentrate from the continual intrusion of sensory input. In hypersensitive states, the mind is preoccupied with avoiding stimuli — noise, light, touch — leading to withdrawal from company [Kent].

Confusion, heaviness, and vertigo, particularly when in the open air or after slight exertion [Allen]. A pressing headache across the forehead and temples, often with nausea, is common. There may be a peculiar sensation as if the head were contracting or shrinking, worse from noise or motion [Clarke].

Photophobia in acute states; eyes feel strained and sore, aggravated by glare or bright sunlight [Hering].

Extraordinary sensitivity to sound, a keynote symptom [Allen]. Even distant conversation or gentle rustling becomes distressing, producing irritability and nervous excitement. This auditory hyperaesthesia may occur in fevers, convalescence, or nervous exhaustion.

Fluent coryza with sneezing and burning in the nasal passages [Boericke]. Discharge is acrid, producing soreness of the nostrils. Crude herb’s historical use as a sneezing powder reflects its strong nasal irritant property.

Pale and drawn during gastric upset. Facial muscles tense from sensory irritation.

Dryness of the mouth with a burning sensation at the tip of the tongue and palate [Allen].

Roughness and burning in the throat, with desire to clear it; worse from inhaling cold air [Hering].

Persistent nausea and inclination to vomit, often unrelieved by vomiting [Allen]. Vomiting of watery or slimy material may occur after eating or from strong odours. Epigastrium is sensitive to pressure. There is marked aversion to food due to nausea.

Cutting, cramping abdominal pains, sometimes followed by diarrhoea [Clarke]. Distension with rumbling.

Soft or watery stools with tenesmus, sometimes alternating with constipation.

Breathing easily disturbed by cold, damp air.

Palpitation during sensory overstimulation [Clarke].

Tightness across the chest, with oppressed breathing [Allen]. Cough provoked by tickling in the throat, worse in cold air.

Sensation of weakness and trembling in the limbs from nervous exhaustion. Tremors aggravated by excitement or noise [Hering].

No primary cutaneous proving symptoms beyond secondary irritation from catarrh.

Restless sleep with frequent waking from slight noises; dreams vivid and disturbing [Allen].

Anxious and active dreams reflecting the day’s sensory irritations [Hering].

Low-grade fevers with great nervous excitability and intolerance of noise [Clarke].

Chilliness in cold, damp air. Sweating on exertion with some relief of tension.

Aversion to food from persistent nausea. Warm drinks soothing; cold drinks aggravating gastric irritation [Allen].

Peculiar and intense over-sensitiveness of the nervous system — the keynote of the remedy. This extends to all senses, but hearing is most affected [Hering]. Gastric symptoms are closely linked with the nervous state.

• Coffea cruda – Hypersensitivity with sleeplessness from overactive mind; Asarum more focused on auditory over-sensitivity.
• Belladonna – Hyperaesthesia during fever but with violent congestion and heat; Asarum lacks marked congestion.
• Nux vomica – Irritability and oversensitivity but with more pronounced digestive spasm and chilliness.
• China – Nervous weakness with hypersensitivity but more from loss of fluids and vital energy.

• Complementary: Nux vomica, Coffea.
• Antidotes: Camphora, Nux vomica.
• Inimical: None known.
• Follows well: Belladonna in certain febrile hypersensitive states.

Valuable in convalescence from prolonged illness when the patient is left in a state of extreme nervous irritability, particularly to noise. Also useful in nervous dyspepsia where nausea and vomiting are aggravated by odours, noise, or motion. In acute catarrhs with hypersensitivity to sound, it may rapidly quiet the nervous system [Hering, Clarke].

Mind:

• Oversensitive to external impressions
• Irritability from noise
• Aversion to company

Head:

• Vertigo in open air
• Pressure in forehead with nausea

Ears:

• Sensitive to noise, slightest sound unbearable
• Hyperaesthesia, auditory

Nose:

• Coryza, fluent, acrid
• Sneezing from irritation

Stomach:

• Nausea from odours
• Vomiting after eating

Extremities:

• Trembling from excitement
• Weakness after exertion

Generalities:

• Oversensitiveness of all senses
• Weakness from nervous exhaustion

Hahnemann S. – Materia Medica Pura: primary proving symptoms on nervous hypersensitivity and gastric irritation.

Hering C. – Guiding Symptoms: keynote of extreme auditory hypersensitivity.

Allen T.F. – Encyclopedia of Pure Materia Medica: detailed proving records of nausea, vomiting, and sensory overreaction.

Hughes R. – Cyclopaedia: pharmacodynamic notes on volatile oils and irritant action.

Clarke J.H. – Dictionary of Practical Materia Medica: acute and convalescent cases.

Kent J.T. – Lectures: mental state in oversensitive patients.

Boericke W. – Pocket Manual: concise keynote references.

Farrington E.A. – Clinical Materia Medica: placing in nervous remedies group.

Lippe A. – Keynotes: mentions auditory hyperaesthesia.

Nash E.B. – Leaders: practical clinical indications for convalescence.