• Stomach & duodenum (primary): Violent hyperacidity, heartburn, and sour regurgitation; acrid vomiting excoriates mouth and throat. Cross-ref. Stomach, Throat, Food and Drink. [Allen], [Clarke], [Boericke]
• Lower oesophagus (GERD/LPR pattern): Burning up the oesophagus, worse night and lying, with acid fluid to mouth; dental sensitivity after reflux. Cross-ref. Mouth/Teeth, Sleep. [Clarke], [Hering]
• Head (frontal/temporal): Frontal headache synchronous with gastric acidity; abates when acidity is checked. Cross-ref. Head, Generalities. [Clarke], [Boericke]
• Bowel fermentation in children: Sour stools, abdominal acidity, napkin excoriation; infantile colic with acid odour. Cross-ref. Abdomen, Rectum, Skin. [Hering], [Clarke]
• Salivary & buccal mucosa: Sour saliva, water-brash; oral smarting from acid; teeth feel “set on edge.” Cross-ref. Mouth, Teeth. [Allen], [Hering]
• Pregnancy nausea/pyrosis: Nocturnal pyrosis and acid vomiting in pregnancy; burning from epigastrium upwards. Cross-ref. Female, Sleep. [Boericke], [Clarke]
• Hepato-biliary (minor): Acid dyspepsia with sense of hepatic weight, but the dominant keynote remains acid rather than biliary. Cross-ref. Abdomen. [Hughes], [Clarke]

• Sitting upright; head high in bed; walking slowly after meals (reduces reflux). [Clarke], [Boericke]
• Dry farinaceous morsels or a little alkaline (e.g., bicarbonate) to blunt the acid for a time. [Hughes], [Clarke]
• Cold water in sips for scalded throat; cool mouth-rinses after acid regurgitation. [Allen], [Clarke]
• Open air after a close, heated room aggravation. [Clinical]
• Small, frequent meals; long gaps worsen burning. [Clarke]
• Looser clothing at epigastrium/waist. [Clinical]
• Dozing propped rather than flat; left-side sometimes (pyloric emptying) better than right. [Clinical]
• Relief of acidity brings frontal headache down (mind–gut link). [Clarke]

• Night; after midnight; lying down, especially right side; on first falling asleep. [Hering], [Clarke], [Boericke]
• After eating, especially sweets, fatty/greasy foods, wine, coffee, and sour fruit. [Allen], [Clarke]
• Stooping or tight belts (increase reflux). [Clarke]
• Pregnancy; dentition in children (acid state). [Boericke], [Hering]
• Warm room or stuffy air; heat of bed provokes heartburn. [Clarke]
• Mental exertion during indigestion (frontal ache mounts). [Clarke]
• Milk in some (curdling and acidity) — compare Aethusa, Mag-c. [Hering], [Clarke]
• Late suppers; eating then lying soon after. [Boericke]

Irritable during acid attacks; activity and thought are narrowed to the burning in the epigastrium and throat. Anxiety may mount on lying down, anticipating the nightly heartburn and sour regurgitation; patients sleep propped and are vexed by even slight errors of diet, a practical rather than constitutional apprehension [Clarke]. Cross-linking to Modalities, the irritability and restlessness rise with night-time reflux and fall when they sit upright or take a little alkaline. Unlike Nux-v., there is less anger and more fretful discomfort; unlike Ars., the anguish is not out of proportion to the pain and is not cooled by sips as a primary craving, but by abating acidity. The mood brightens in the cool air or after walking, when reflux is quieter. During pregnancy, fear of bedtime appears if every night ends in acid vomiting, a pattern specifically attested in the clinical notes [Boericke], [Clarke]. [Clinical]

A frontal, pressing headache synchronises with the gastric storm and is most troublesome at night; it relents if the acidity is relieved by upright posture or a small alkaline [Clarke]. Head feels hot while face may be pale; temples throb after rich foods. Unlike Iris-v., which has a periodic sick-headache with acrid vomiting and burning, Rob. is less migrainous and more continuously tied to heartburn and sour reflux. The patient often wakes with a dull front head after a night of heartburn; clearing the stomach and keeping upright thins the ache. [Boericke], [Clarke]. [Clinical]

Smarting and lachrymation when sour eructations reach the naso-pharynx; vision dims transiently with the frontal ache. There is no intrinsic ocular disease; eye strain mirrors the cephalic and gastric axis and lifts as acidity abates. [Clarke]. [Clinical]

Fullness or humming with the headache nights; ear symptoms are reflex and pass with the stomach relief. There is no otic pathology proper. [Clinical]

Acrid vapour from regurgitation irritates posterior nares; sneezing or snuffling at night is reported in children with sour reflux. Again the sign is derivative of the gastric process. [Hering]. [Clinical]

Pale, drawn, with lip-burning after acid runs to the mouth; a sour odour is noticed in children. Teeth are “set on edge” by the acid—a distinctive subjective that cross-links with Mouth/Teeth. Face grows more comfortable on sitting up in bed and sipping cool water. [Clarke], [Allen]. [Clinical]

Sour saliva, water-brash, and an acid taste dominate; the mucosa stings from regurgitated fluid, and gums feel tender after nocturnal reflux [Allen], [Hering]. The tongue may be coated white or yellowish after a night of heartburn; breath sour. Rinsing cool water gives immediate comfort but only holds while the stomach continues to pour acid. Compare Rheum (sour saliva with fermenting stools in children); in Rob. the mouth is burnt by upward acid more than by intestinal fermentation. [Clarke]. [Clinical]

Teeth are sensitive and feel “set on edge” after each rush of sour fluid; cold water rinses soothe, but enamel remains tender through the night. There may be a dragging ache at roots after a heavy meal when lying. This dental sensitivity is secondary and fades as reflux is controlled, a practical cross-link to Better upright / after alkalies. [Allen], [Clarke]. [Clinical]

Acrid, burning track from cardia to fauces; scraping, cough-like clearing after regurgitation; hoarseness in the morning after a bad night, suggesting laryngo-pharyngeal irritation from acid [Clarke]. Swallowing is painful for a time after vomiting; cool drinks relieve the scald; warm draughts often aggravate the sore fauces, though the stomach may like warmth. [Allen]. [Clinical]

This is the centre: excessive acidity, intense heartburn, and sour regurgitations which wake after midnight and stream to the mouth on lying, with burning from epigastrium to throat [Hering], [Clarke]. The vomited matter is sour and acrid, excoriating mouth and fauces; there may be nausea all evening, worse after sweets or wine, and a compulsion to sit up to breathe and swallow less acid. Unlike Nux-v., which has gastric irritability from diet/stimulants with cramp and ineffectual retching, Rob. is a purely acid storm with marked oesophageal burning and night-worse pattern; unlike Phos., there is little thirst for cold drinks as a keynote, and little craving for ice. Iris-v. overlaps in acrid emesis but is more periodic sick-headache and burning diarrhoea; Rob. centres the reflux. A small amount of farinaceous food or an alkali may quiet the burn for an hour, cross-linking to Better dry morsels / alkalies. [Boericke], [Clarke], [Allen]. [Clinical]

Heaviness and fulness in epigastrium with gas and sour risings; umbilical uneasiness in children with sour stools. The abdomen is sensitive to belts and bending forward; walking easy after the first hour post-prandially. Gas collects without the Lycopodium right-hypochondrium keynote; the odour is acid rather than offensive. [Clarke], [Hering]. [Clinical]

Urine sometimes hot or scalding after nights of heartburn; meatus tingles in children when the skin is excoriated by acids. No specific renal lesion is intended. [Clinical]

In children: sour, excoriating stools; napkin rash; urging after fruit or sweets; the stool may be greenish or pappy but is acid to nose and skin [Hering], [Clarke]. Adults less often diarrhoeic; constipation alternates with acid stools after indiscretion, but the rectal sphere is secondary to the stomach–oesophagus complex. The sour odour distinguishes from Merc. (foul) and Podoph. (copious, gushing morning). [Boericke]. [Clinical]

Acid pyrosis after late suppers or alcohol; sexual sphere not characteristic. A sense of dragging after stooping soon translates back to the stomach. [Clinical]

Heartburn of pregnancy, particularly night and on lying, with sour vomiting, burning from stomach to throat, and sensitivity to sweets and coffee [Boericke], [Clarke]. Many must sleep propped; a light, dry biscuit at bedtime may check the first rise of acid. Distinguish Nux-v. (nausea on waking with irritable temper) and Puls. (rich foods, bland thirstless state). [Clinical]

Short and anxious during a reflux paroxysm in bed; better sitting up at the window. Breath odour sour in the night; morning hoarseness from laryngeal splash. [Hering], [Clarke]. [Clinical]

Palpitation from distress and recumbent aggravation; subsides when patient gets upright and the burning calms. The heart here is reactive to oesophageal pain rather than diseased. [Clarke]. [Clinical]

Burning behind sternum tracks each reflux wave; a dry cough from throat-rawness at night; chest tightness abates when sitting up or after a cool sip. No primary pulmonary disease is suggested. [Clarke]. [Clinical]

Between-scapula burning or aching as acid lies behind the sternum; posture adjustment gives relief. The back symptom is referred from the oesophagus. [Clinical]

Restlessness of legs with nightly heartburn; heaviness after meals improves on walking gently. No primary rheumatic sphere. [Clinical]

Infants show napkin excoriation from sour stools; adults may note lip-chapping after acid vomiting. The cutaneous signs are acid-burn sequelae. [Hering], [Clarke]. [Clinical]

Sleep is broken after midnight by heartburn and sour regurgitation that compels the patient to sit up or walk; lying down again rekindles the burning and sour flood [Clarke], [Boericke]. Patients experiment with pillows and upright dozing; those who learn to avoid late suppers sleep more steadily—an explicit cross-reference to Modalities. Children cry out and startle with a sour burp; once propped and the mouth rinsed, they drowse, only to wake again in an hour. The frontal headache of Rob. is often a consequence of a broken, acid night and fades as sleep improves. [Clinical]

Dreams of smoke or burning in the throat; of eating sweets and paying for it; of choking on sour fluid. These decrease as nocturnal reflux is controlled. [Clinical]

No specific fever state; heat of face and scalp-sweat may accompany a night attack but reflect exertion and irritation. [Clarke]. [Clinical]

Heat in chest and face with heartburn; slight sweat after a vomiting spell; chills are not characteristic. Thermal swings follow the gastric paroxysm, not vice versa. [Allen], [Clarke]. [Clinical]

Worse from sweets, fat, wine, coffee, sour fruits, and late meals; milk may curdle and aggravate in some, while others use a small dry biscuit or alkaline to better the first reflux [Allen], [Clarke], [Hering]. Appetite is present but cautious; the patient learns to eat small, frequent, dry portions and to keep upright afterwards—dietary rules that dovetail the remedy’s modalities. [Clinical]

Robinia is the pure acidity remedy: hyperacidity, nocturnal heartburn, sour regurgitation and vomiting with burning from stomach to throat, worse at night, lying, after sweets and fats, better upright, propped, and from small alkalies [Clarke], [Boericke], [Allen]. The frontal headache belongs to the same process and is relieved when the acid storm abates. Children manifest the acid theme as sour stools and napkin excoriation; pregnancy bears it as night pyrosis. Differentiate from Iris-v. (periodic sick-headache with acrid emesis and burning diarrhoea), Nux-v. (gastric irritability with spasms, temper, morning nausea), Rheum (general sourness with umbilical colic and chill during stool in infants), Mag-c. (milk intolerance with sour stools and chilliness), Phos. (heartburn with craving cold drinks and easy vomiting of water), Sul-ac. (tremulous, rapid sinking, craving alcohol; acid states with haemorrhagic tendency), and Carbo-veg. (flatulence, burning, but with collapse and desire to be fanned). The clinical logic is straightforward: when night reflux with sour burning dominates the case and mechanical anti-reflux measures plus small alkalies give prompt, partial relief, Rob. completes the cure. [Clarke], [Hering], [Boericke], [Hughes]. [Clinical]

• Hyperacidity / reflux (night, lying)
  • Iris versicolor — Acrid, burning vomit with periodic sick-headache and often burning diarrhoea; more migraine-cycle than Rob.’s steady night reflux. [Clarke], [Boericke].
  • Nux vomica — Dyspepsia from stimulants and late meals with spasm, irritability, morning nausea; less fixed sour flood at night than Rob.; Nux is often antecedent in overworked gourmands. [Clarke], [Hering].
  • Phosphorus — Heartburn, regurgitation; craves cold drinks, vomits when warm; burning yet “empty” feeling; less purely acid than Rob. [Hughes], [Clarke].
  • Sulphuric acid (Sul-ac.) — Profound acidity with tremulous weakness, haemorrhagic tendency, and desire for alcohol; oesophageal burn present but systemic tone differs. [Allen], [Clarke].
  • Carbo vegetabilis — Heartburn with flatulent distension and collapse, wants to be fanned; eructations easier than in Rob.; less nightly reflux focus. [Boericke].
  • Kali bichromicum — Burning, heaviness, stringy mucus, gastric ulcer type; not the clean sour flood of Rob. [Clarke].
• Sour child / dentition diarrhoea
  • Rheum — Sour everything with umbilical colic, chill during stool, brief relief after stool; overlaps but is bowel-fermentation rather than upward acid reflux. [Hering], [Clarke].
  • Magnesia carbonica — Milk intolerance, green sour stools, chilly thin child; Rob. shows more nocturnal heartburn in nursing mother and sour stool in infant without the Mag-c. craving. [Phatak].
  • Calcarea carbonica — Sour head-sweat with dentition but commonly constipation; Rob. guides when stools or vomit are sour with acid regurgitation. [Tyler], [Boericke].
• Pregnancy pyrosis
  • Pulsatilla — Rich-food indigestion, bland tongue, thirstless; heartburn not necessarily nocturnal; emotional softness; Rob. is more night reflux and sour flood. [Clarke].
  • Sepia — Nausea with empty sinking, bearing-down; heartburn may occur but not with the persistent sour regurgitation of Rob. [Boericke].

• Complementary: Nux-v. in diet/stimulant dyspeptics—Nux re-sets irritability; Rob. then resolves the acid reflux residue. [Clarke], [Hering].
• Complementary: Rheum/Mag-c. where the infant shows sour stools or milk intolerance while the nursing mother needs Rob. for her night reflux. [Hering], [Phatak].
• Follows well: Iris-v. when periodic sick-headache has been broken but a steady nocturnal acidity persists. [Clarke].
• Precedes well: Nat-phos. as a tissue balancing measure in chronic acid states once acute reflux settles (clinical usage). [Boericke].
• Compare: Phos., Sul-ac., Carb-v., Puls., Sep., Kali-bi.—see Differentials above.
• Practical measures (synergy): Avoid late suppers; elevate head of bed; small, dry meals; loosen belts—mechanical complements repeatedly noted by the old authors and echoed in Modalities. [Clarke], [Boericke].

• Night reflux/heartburn with sour vomiting; lying-worse: Rob. 6x–30C at bedtime (and on waking with heartburn), along with head elevation and late-meal avoidance; step to 30C–200C for persistent nightly flares after triggers are controlled. [Clarke], [Boericke]
• Pregnancy pyrosis: Rob. 30C at dusk; small dry biscuit at lights-out; avoid sweets and coffee; sleep propped. Distinguish Puls. and Sep. when sourness is not central. [Boericke], [Clarke]
• Sour child: If reflux up is conspicuous, consider Rob.; if umbilical colic/chill during stool predominate, prefer Rheum; switch if the picture declares. [Hering], [Clarke]
• Headache–acid link: In recurrent frontal headaches of dyspeptics, test the Rob. hypothesis by posture and alkaline trial while prescribing—headache often falls as acid recedes. [Clarke]

Head / Mind

• HEAD — PAIN — frontal — night — with heartburn; acidity — during. — Frontal ache tracks acid state. [Clarke]
• MIND — ANXIETY — at night — heartburn; from. — Anticipates reflux on lying. [Clarke]

Mouth / Throat / Teeth

• MOUTH — SALIVA — sour — waterbrash — with. — Classic water-brash of acid states. [Allen]
• TEETH — SENSITIVE — after acids — eructations; from — “teeth on edge.” — Dental sequelae of reflux. [Clarke]
• THROAT — BURNING — oesophagus — regurgitation of acid — from — night. — Oesophageal scald of reflux. [Hering], [Clarke]

Stomach (core)

• STOMACH — ACIDITY — excessive — night. — Keynote hyperacidity after midnight. [Boericke]
• STOMACH — HEARTBURN — lying — aggravates — night — aggravates. — Posture and time modalities. [Clarke]
• STOMACH — ERUCTATIONS — sour — with burning. — Acid air and burn together. [Allen]
• STOMACH — VOMITING — sour — night — after lying down. — Sour flood of the night. [Hering]

Abdomen / Rectum / Skin (child)

• STOOL — ODOUR — sour — children — excoriating. — Sour napkin rash. [Hering], [Clarke]
• SKIN — EXCORIATION — from stools — sour. — Acid burn of perineum. [Hering]

Modalities / Generals

• GENERALITIES — POSITION — lying — aggravates — complaints of stomach. — Reflux posture. [Clarke]
• GENERALITIES — FOOD and DRINKS — sweets — aggravate; fat — aggravates; wine; coffee — aggravates. — Dietary triggers. [Allen], [Clarke]
• GENERALITIES — EATING — after — aggravates — heartburn. — Post-prandial burn. [Boericke]
• SLEEP — WAKING — after midnight — heartburn — from. — Night wake with reflux. [Clarke]

Allen, T. F. — Encyclopaedia of Pure Materia Medica (1874–79): toxicology and clinical notes—sour regurgitation, acrid vomiting, water-brash, dental “on edge.”
Hering — The Guiding Symptoms of Our Materia Medica (1879): night-worse heartburn; sour stools of children; pregnancy pyrosis confirmations.
Clarke — A Dictionary of Practical Materia Medica (1900): remedy portrait—nocturnal reflux, frontal headache tied to acidity; regimen (posture, diet).
Boericke — Pocket Manual of Homoeopathic Materia Medica (1901): keynotes—hyperacidity, heartburn at night, lying-worse; pregnancy application.
Hughes — A Manual of Pharmacodynamics (1870s): toxicologic background (bark alkaloids), gastric irritant arc informing remedy sphere.
Boger — Synoptic Key of the Materia Medica (1915): modality grid—night, lying, sweets/fats aggravate; comparisons with Iris-v., Nux-v., Phos.
Farrington — Clinical Materia Medica (late 19th c.): differentiations of acid remedies (Iris-v., Sul-ac., Phos., Nux-v.) in dyspepsia.
Nash — Leaders in Homoeopathic Therapeutics (1907): practical hints in hyperacidity and reflux; food and posture rules.
Dewey — Practical Homoeopathic Therapeutics (1901): pregnancy heartburn therapeutics; diet counsel.
Tyler — Homoeopathic Drug Pictures (1942): reminders for sour child vs maternal reflux; contrasts with Puls., Sep.
Phatak — Concise Materia Medica (1977): comparisons in sour children—Mag-c., Calc-c., Rheum; triggers (milk, sweets).
Dunham — Lectures on Materia Medica (1870s): clinical observations on posture and timing in gastric remedies.