• Stomach & Duodenum. Acid dyspepsia: sour eructations/heartburn, sour vomiting (infants), intolerance of fats and rich foods; emptiness with acidity [Hering], [Allen], [Boericke], [Clarke].
• Intestines (Infants). Greenish, sour, curdled stools; diarrhoea after milk; pin-worms with itching anus, worse at night [Hering], [Allen], [Clarke], [Boericke].
• Metabolism (Acid–Alkali). Uric-acid diathesis: urates in urine, gravel, gout; lactic-acid excess after exertion; sour sweat; tendency to acetonaemia in children [Schussler], [Clarke], [Boger], [Phatak].
• Mucosae (Yellow–creamy). Canary-yellow or lemon-yellow creamy coating on back of tongue; yellow creamy nasal or faucial discharge/patches [Clarke], [Boericke], [Allen].
• Throat. Follicular pharyngitis with yellow creamy exudate; subacute tonsillitis, post-diphtheritic catarrh (not a membrane remedy) [Clarke], [Boger].
• Joints & Tendons. Gouty and lactic-acid myalgias; tennis-elbow insertions sore; morning stiffness in uratic subjects [Boger], [Phatak], [Boericke].
• Urinary. Acid urine, phosphates/urates; brick-dust sediment; thread-worms and enuresis with acidity [Allen], [Clarke].
• Skin. Acid urticaria, especially after shellfish or sweets; intertrigo excoriated by sour sweat [Boericke], [Clarke].
• Head & Nerves. Sick-headache from acidity (after fats, pastry, sweets), with yellow-coated tongue base and sour risings [Nash], [Clarke].
• Female & Lactation. Acid dyspepsia in pregnancy; vomiting sour, infant colic from rich milk; nipple fissures with creamy discharge (adjunct) [Clarke], [Boericke].

• Alkaline drinks or food; bicarbonate-containing water; milk diluted with alkaline water [Clarke], [Boericke], [Schussler].
• Moderate eating; light, plain diet (dry toast, simple cereals) [Nash], [Clarke].
• Eructations; bringing up wind; gentle walking after meals [Allen], [Clarke].
• Warmth of abdomen; hot-water bottle for cramp but not for heartburn [Boger].
• Early evening light meal; avoiding late suppers [Nash].
• Sitting upright after food; avoiding recumbency [Clarke].
• Avoiding sour/acid foods (citrus, vinegar, pickles) and rich fats [Boericke].
• Short nap after relieving stool in infants (post-acid diarrhoea lull) [Hering].
• Bathing eruptions with mild alkaline lotion (urticaria, chafing) [Clarke].
• Rest after over-exertion in lactic-acid myalgia; stretching then warmth [Boger].
• Cool rooms for bilious-acid sick headache; fresh air without draught [Nash], [Clarke].
• Regular bowel routine (prevents sour fermentation) [Clarke].

• Sour/acid foods (citrus, vinegar), sweets/sugar, pastry, fats, ice-cream [Allen], [Boericke], [Clarke].
• Milk (undigested → curdled vomiting, sour stools), especially in infants [Hering], [Allen].
• Night, especially after midnight: worms, sour risings, heartburn, itching anus [Hering], [Allen], [Clarke].
• Over-eating or hurried eating; eating late at night [Nash], [Clarke].
• Physical exertion (lactic-acid myalgia, tendon soreness) [Boger], [Phatak].
• Weather changes toward damp cold (gouty stiffness, urticaria) [Phatak], [Boericke].
• Mental work after meals (sick-headache, sourness) [Nash], [Clarke].
• Lying on right side after food (heartburn, sour regurgitation) [Clarke].
• Beer, sweet wines, and shellfish (urticaria, gastric upset) [Clarke], [Boericke].
• Acid sweat or sour diapers excoriating skin (intertrigo) [Hering], [Boericke].
• Suppression of usual stool (fermentation increases) [Clarke].

The Nat-p. temperament is digestively coloured: irritability and peevishness rise and fall with acidity, smoothing as the stomach quiets (Stomach cross-link) [Clarke], [Nash]. Mental work after meals triggers a sour-headed confusion—ideas dull, averse to exertion, relieved by a walk and a small alkaline draught (Modalities) [Nash], [Clarke]. Children are fretful, cry before the sour, curdled stool, then grow placid until the next feed; the diaper’s sour odour is diagnostic (Intestines/Skin) [Hering], [Allen]. Anxiety is practical, centred on food choices and fear of “biliousness”; they read labels to avoid acid/sugar, a coping trait learned by relapse (Food & Drink) [Clarke]. Gouty subjects grow snappish in damp weather, worsened by heaviness in feet and morning stiffness (Joints) [Phatak], [Boger]. Melancholy is mild, dyspeptic—a yellow-tongued gloom that lifts with a good alkaline day; there is none of the deep weeping of Nat-m. (Differential) [Clarke], [Kent]. In headaches they seek quiet and cool air, dislike fuss; if pressed to eat they grow irritable (Head/Modalities) [Nash]. Students complain of “foggy” head after sweets/pastry; a glass of alkaline water and a walk restore clarity (Affinities: Metabolism) [Clarke]. During worm aggravations the child is restless at night, grinds teeth, and is cross on waking until bowels move (Intestines) [Hering]. Overall the mind tracks acidity: as sour risings ebb, the temper steadies and attention returns [Clarke], [Nash], [Boericke].

Sick-headache from acidity: dull frontal or bi-temporal ache with yellow-coated tongue base, sour risings, and nausea after sweets/fats or study after meals; better alkalies, open air, and gentle walking (Stomach link) [Nash], [Clarke], [Boericke]. A band-like pressure accompanies heartburn, rising after late suppers (Modalities) [Clarke]. In uric-acid subjects, morning heaviness and dizzy turns on rising occur when urine is scant and brick-dust sediment appears (Urinary) [Clarke], [Boger]. Headache in damp changes with joint stiffness (Metabolism/Joints) [Phatak]. Children with acid diarrhoea moan and burrow the head in pillow, settling after a stool (Intestines) [Hering]. Light and noise are not extreme aggravations; the gastric–metabolic axis is the true driver [Nash], [Clarke].