Remedy relationships are the recorded observations, accumulated since Hahnemann, of how homeopathic remedies behave in sequence: which remedy completes another's work (complementary), which follows another well, which pairs are said to interfere with each other (inimical), and which counter another remedy's action (antidotes). They are prescribing traditions written down by named authors, not demonstrated interactions, and they are read by practitioners choosing a second prescription, not by patients deciding what to take. The name attached to each note matters, because the lists do not agree and were never meant to be merged.
In short: A remedy relationship is a named author's note on what happened when one remedy followed another. The four labels you will meet are complementary, follows well, inimical and antidote; the tables behind them run from Hahnemann's remedy prefaces through Boenninghausen, Hering, Boericke and Clarke. Hahnemann's prefaces and the Hering, Boericke and Clarke sections are readable free on Similia's public materia medica pages; Boenninghausen's concordances are a repertory chapter, carried into the BBCR. The in-app Relationships view that merges the materia medica sources is a Pro feature. This is a reference for practitioners and students, not treatment guidance.
The four relation types, defined
Terminology drifts between authors. Hering writes "compatible" and "incompatible" and splits compatible into "before" and "after"; Clarke prefers "follows well" and "followed well by"; Boericke compresses everything into one line. The four groups below cover all of it.
Complementary
A complementary remedy is one reported to complete or continue another's action once the first has done what it can. Farrington's lecture on Nux vomica gives the clearest definition in the literature: "Nux vomica is complementary to Sulphur. By that I mean that very frequently after Nux vomica has done as much as its symptoms will allow it to do, the remaining symptoms often find in Sulphur the remedy that will complete the cure" (A Clinical Materia Medica, 2nd ed., 1890; read the lecture free). Nash states the same kind of pairing in a single sentence for Carbo vegetabilis, "China is its great complementary", and writes Kali carbonicum up as "Complementary to Carbo vegetabilis" (Leaders in Homoeopathic Therapeutics, 4th ed., 1913).
Complementarity is often mutual but not always. Boericke gives Natrum mur and Sepia as complementary to each other, and Farrington agrees that "these remedies are complementary to each other". Yet Boericke lists Silicea among the complements of Phosphorus, while Silicea's own line names Thuja, Sanicula, Pulsatilla and Fluoric acid and does not return the favour. Read the entry for the remedy already given, not only the one you are considering.
Follows well, followed well by
The direction matters, and the careful authors record it. Clarke's Calcarea entry lists "Follows well: Cham., Chi., Con., Cup., Nit. ac., Nux, Pul., Sul." and separately "Followed well by: Lyc., Nux, Pho., Plat., Sil.", then adds that "Hahnemann says that Calc. must not be given before Nit. ac., or Sul." So Sulphur then Calcarea is recorded as a good sequence, and Calcarea then Sulphur is warned against. Boericke's Sulphur line makes the same point from the other side, "Mercur and calcarea are frequently useful after Sulphur, not before", and H. C. Allen's Keynotes repeat it as "Calcarea must not be used before Sulphur".
Farrington's lectures are full of the directional form: "Phosphorus is the remedy which most frequently follows Nux" in the cerebral cases he has just described. Nash writes of Nitric acid that "If Mercurius has already been used without avail Nitric acid follows well and will often cure". Because A follows B does not mean B follows A, a properly built table keeps two columns, the split between "Follows well" and "Followed well by" that Similia's Relationships view preserves.
Inimical (incompatible)
An inimical remedy is one an author advises against giving directly after another, because the two are said to interfere. Farrington on Apis and Rhus tox: "You should be particular in differentiating these remedies, because they are inimical, and one cannot be given after the other." On Silicea and Mercurius: "Mercurius does not follow well after Silicea. Their symptomatologies are apparently similar, and yet they do not seem to agree, although Silicea will antidote some of the effects of mercury, but, as potentized medicines, they do not follow each other well." And on Nux: "Nux vomica is inimical to Zinc", mirrored in his Ignatia lecture, where Zincum "follows Ignatia well, while it is inimical to Nux vomica".
Boericke and Clarke carry all three pairs, which is why every student learns them. Both also mark Bryonia incompatible with Calcarea and Causticum with Phosphorus, and Boericke adds that Sulphur should not be given after Calcarea. Beyond these the lists diverge. Boericke lists Lachesis and Pulsatilla as inimical to Sepia; Clarke keeps only Lachesis, and records one case in which Sepia in high potency proved the antidote to a Lachesis aggravation. Inimical lists are short, partly contested and author-dependent, so quote the author.
Antidotes
The word antidote carries two senses in the relationship tables. The first is the crude substance said to cancel a remedy's action, and it goes back to Hahnemann's own remedy prefaces. In Materia Medica Pura he writes of Arnica that "Camphor is the antidote for large doses in unhomeopathic cases, but wine aggravates its injurious effects" (Arnica, Hahnemann), and in The Chronic Diseases of Aurum that "An antidote to its excessive effects has been found in the smelling of a potentized preparation of crude coffee, and more especially of camphor" (Aurum, Hahnemann). Kent's Camphora lecture calls the camphor bottle a great mischief in the house, because camphor "antidotes most of our remedies" (Camphora, Kent).
The second sense is the potentised remedy said to counter another's over-action or abuse. Farrington opens his Mercurius lecture with a board full of them and singles out one: "Hepar is the most important antidote for Mercury, and also for many of the other metals" (Mercurius, Farrington). Of Phosphorus he says "Nux vomica is good when Phosphorus, as a remedy, has produced over-effects, or when it has been incorrectly given." Clarke's Pulsatilla entry describes the reciprocal case: "Cham. and Puls. antidote each other and follow each other well. If either one has over-acted the other will probably neutralise the ill effect and carry on the good."
Both senses are historical labels within a prescribing tradition. Neither is a medical antidote to poisoning, and the tables do not establish a response to an adverse reaction.
Where the relationship tables come from
Nobody wrote a relationship table from scratch. The tables accreted, and knowing the layers explains why they disagree.
Hahnemann's remedy prefaces in Materia Medica Pura (1811 to 1821) and The Chronic Diseases (1828) carry the first notes, almost all antidotes and cautions about sequence. Boenninghausen's Therapeutic Pocketbook (1846) turned sequence into a repertory chapter, the concordances, listing for each remedy the medicines observed to relate to it. Hering's Guiding Symptoms of Our Materia Medica (1879 to 1891) gave every remedy a numbered section 48, "Relations", with antidotes, compatible and incompatible remedies and comparisons, and Knerr's repertory of the Guiding Symptoms indexed the work. Farrington's lectures (second edition 1890) taught relationships from the blackboard, remedy by remedy.
Around the turn of the century the tables were consolidated. H. C. Allen's Keynotes (1899) carries a bold "Relations" line near the end of each remedy, before Aggravation and Amelioration. Clarke's Dictionary of Practical Materia Medica (1900 to 1902) gives the richest apparatus of all: antidoted by, antidote to, compatible, follows well, followed well by, incompatible, complementary and compare, often with an explanatory clause after each name. Boericke's Pocket Manual (1901; ninth edition 1927) compressed the same information into the single "Relationship" line most students meet first. Phatak and later compilers gathered the accumulated lists into charts and single volumes.
Two consequences follow. A later table usually copies an earlier one, so agreement between Boericke and Clarke is often one observation counted twice. And when the tables disagree, that is information: an observation did not travel. Our guides to the BBCR concordances, Clarke's Relations section and Boericke's Relationship line cover each layer in its own context.
Reading a relationship section in the classical books
All four books below are in Similia's free library, and each remedy page links to the same remedy in the other authors.
Boericke's "Relationship" line
Boericke closes every entry with three labelled lines: Modalities, Relationship and Dose. The Relationship line runs "Complementary", "Compare", "Antidotes" and, where recorded, "Inimical" or "Incompatible", with follows-well notes tucked into the Compare list. Sulphur reads: "Complementary: Aloe; Psorin; Acon; Pyrarara" and "Compare: Acon (Sulph often follows in acute diseases); Mercur and calcarea are frequently useful after Sulphur, not before." The sequencing rule about Calcarea sits inside "Compare", not under its own heading.
Clarke's "Relations"
Clarke's "Relations" paragraph is the fullest in the classical literature, and it is where a second prescription is usually checked. Nux vomica opens with "Antidoted by: Wine, Coffee, Aco., Bell., Camph., Cham., Coccul., Op., Pal., Plat., Stram., Thuj.", continues with "Compatible after: Ars., Ipec., Mg. mur., Pho., Sep., Sul. Compatible before: Bry., Pul., Sul. Complementary: Sul. (Calc.). Incompatible: Zinc.", and then adds the kind of aside no chart can hold: "In clearly Nux cases Sep. follows better than Puls." The "Compare" list that follows runs for a page and is a differential by condition; read Clarke for the reasoning behind a relationship, not only the name.
Hering's section 48 and Allen's "Relations"
Hering numbers every remedy's schema from 1 (Mind) to 48 (Relations), so the relationship section is always in the same place and always labelled the same way. Calcarea carbonica gives "Antidotes: Camphor, Ipec., Nitr. ac., Nitr. spir. dulc., Nux vom., Sulphur", "Compatible: before Lycop., Nux vom., Phosphor., Platin., Silica; after Chamom., Cinchon., Conium, Cuprum, Nitr. ac., Nux vom., Pulsat., Sulphur", "Incompatible: before Nitr. ac. and Sulphur, according to Hahnemann" and "Complementary to Bellad." Hering's "before" and "after" are followed-well-by and follows-well.
H. C. Allen's Keynotes carry a bold "Relations" line near the end of each remedy that reads like a teacher's summary. Lycopodium: "Complementary: Iodine", then "Follows well: after, Calc., Carbo v., Lach., Sulph. It is rarely advisable to begin the treatment of a chronic disease with Lyc. unless it is clearly indicated; it is better to give first another antipsoric." Similia's reader shows both as their own sections on the remedy page.
Twelve polychrests: a compact relationship table
Key: B. Boericke, C. Clarke, F. Farrington, H. Hering, A. H. C. Allen. Each cell names its author; where authors disagree, both are given rather than merged. Cells are selective, not exhaustive.
| Remedy | Complementary | Follows well (after) | Inimical / incompatible | Antidoted by | Read |
|---|---|---|---|---|---|
| Sulphur | B.: Aloe, Psorinum, Aconite · C.: Aloe, Aconite, Nux, Pulsatilla (Sulphur is "the chronic" of the last three) | C.: Mercurius; Sulphur, Calcarea, Lycopodium "frequently follow in this order" · A.: same | None listed by B. or C.; C.: Calcarea "should not be used before Sul." | C.: Aconite, Camphor, Chamomilla, Mercurius, Pulsatilla | Boericke |
| Calcarea carb | B.: Belladonna, Rhus, Lycopodium, Silicea · C., H.: Belladonna | C.: Chamomilla, China, Nux, Pulsatilla, Sulphur; followed well by Lycopodium, Phosphorus, Silicea | B., C.: Bryonia · B.: Sulphur not after Calc. · C., H.: not before Nitric acid or Sulphur (Hahnemann) | B.: Camphor, Ipecacuanha, Nitric acid, Nux · C. adds Sulphur | Boericke |
| Lycopodium | B.: Iodum, Graphites, Lachesis · A.: Iodine | C.: Sulphur, Calcarea, Lachesis · A.: Calcarea, Carbo veg, Lachesis, Sulphur | C.: coffee; none named by B. | B.: Camphor, Pulsatilla, Causticum · C. adds Aconite, Chamomilla, Nux | Boericke |
| Nux vomica | B.: Sulphur, Sepia · C.: Sulphur (Calcarea) · F.: Sulphur | C.: after Arsenicum, Ipecacuanha, Phosphorus, Sepia, Sulphur · F.: Phosphorus most often follows (in the cerebral cases) | B., C., F.: Zincum | C.: wine, coffee, Aconite, Camphor, Chamomilla, Cocculus, Opium | Boericke |
| Pulsatilla | B.: Coffea, Chamomilla, Nux · C.: Lycopodium, Sulphuric acid, Argentum nit, Stannum | C. (Compatible): Arsenicum, Bryonia, Lycopodium, Nux, Sepia, Sulphur; Chamomilla and Puls "follow each other well" | None listed by B. or C. (B. lists Puls as inimical under Sepia) | F.: Chamomilla, Coffea, Ignatia, Nux · C.: same; Teste adds Sulphur | Boericke |
| Sepia | B.: Natrum mur, Phosphorus · C.: Natrum mur, Natrum carb, Sulphur · F.: Natrum mur | C.: followed well by Nitric acid · B.: Guaiacum "often beneficial after Sepia" | B.: Lachesis, Pulsatilla · C.: Lachesis only, with a recorded exception | C.: sweet spirits of nitre, vegetable acids, Aconite, Rhus | Boericke |
| Natrum mur | B.: Apis, Sepia, Ignatia · C.: Apis, Sepia, Capsicum · F.: Argentum nit, Apis, Sepia | C.: before Sepia, Thuja; after Kali mur, Kali phos, Kali sulph, Natrum sulph | None: F. "I do not now recall any remedy inimical to Natrum mur." | B.: Arsenicum, Phosphorus, sweet spirits of nitre · C.: same | Boericke |
| Phosphorus | B.: Arsenicum, Cepa, Lycopodium, Silicea · C.: Arsenicum, Cepa, Carbo veg, Ipecacuanha · F.: Arsenicum, Allium cepa | B.: Tuberculinum "follows Phosphor well" · C. (Compatible): Arsenicum, Calcarea, Lycopodium, Nux, Sepia, Sulphur | B., C.: Causticum | F.: Nux, Terebinthina · C.: Nux, Coffea, Terebinthina | Boericke |
| Silicea | B., C.: Thuja, Sanicula, Pulsatilla; B. adds Fluoric acid | C.: Calcarea, Graphites, Hepar, Phosphorus; followed well by Lachesis, Lycopodium, Sepia | B., C., F.: Mercurius ("do not follow each other well") | C.: Camphor, Hepar, Fluoric acid | Boericke |
| Mercurius | B.: Badiaga · C.: none under its own heading, but calls Belladonna "often complementary" under Compare | C.: after Aconite, Belladonna, Hepar, Lachesis, Sulphur · B.: after Sulphur, not before | C.: Silicea ("never … immediately before or after each other"); none named by B. | B.: Hepar, Aurum, Mezereum · C. adds Nitric acid, China, Kali iod · F.: Hepar "the most important" | Boericke |
| Apis | B., C., F.: Natrum mur ("the chronic" of Apis); B. adds Baryta carb | C.: Bryonia, Iodum, Sulphur; followed well by Arsenicum, Phosphorus | B., C., F.: Rhus tox; C. adds "in eruptive diseases" | C.: Natrum mur "in all forms", Ipecacuanha, Lachesis, Ledum | Boericke |
| Rhus tox | B.: Bryonia, Calc fluor; Phytolacca in rheumatism · C.: Bryonia | C.: Arnica, Arsenicum, Bryonia, Calcarea; followed well by Calcarea, Nux, Phosphorus, Sulphur | B., C., F.: Apis; C. "before or after, especially in skin affections" | C.: Bryonia, Belladonna, Camphor, Coffea, Mercurius, Sulphur | Boericke |
This is a study table, not a prescribing rule. It stops deliberately at twelve remedies, because reproducing a whole chart adds nothing the books do not say better. Every other remedy's Relationship, Relations and section 48 is one click away in the free materia medica library, and each Boericke page above links to the same remedy in Clarke, Hering, Allen, Farrington and the rest.
How practitioners actually use relationships
Relationship tables are consulted at four moments in a case; this section describes prescriber method only.
The second prescription. A well-chosen remedy has acted, the picture has shifted, and the remaining symptoms no longer fit the first remedy. Complementary and follows-well lists are the first place to look, because they record which remedies have picked up where another left off. The antipsoric trio is the standard example: Nash writes of Lycopodium that "This remedy with Sulphur and Calcarea form the leading trio of Hahnemann's anti-psoric remedies", and Clarke, Hering and Allen all record the three as following one another in that order. Our polycrest guide and Sulphur guide cover the pictures; the relationship note only tells you which entries to open once the totality has changed.
The check before prescribing. Before a second remedy is given, its name is checked against the previous remedy's inimical list. If Apis has just acted and Rhus tox now seems indicated, Farrington says to differentiate the two with particular care, and Boericke and Clarke both list the pair as inimical. The check takes thirty seconds.
Reading the follow-up. Both moments above depend on reading what a remedy has done, which is a separate skill. Our guide to Hering's law and the direction of cure covers how to distinguish improvement from a shifted picture, and a new symptom from an old one returning. An "antidoted by" entry is read when a well-chosen remedy has plainly over-acted, in Clarke's phrase; the response in a given case is a clinical decision, not something a table settles.
The differential. Boericke's "Compare" list, Clarke's condition-by-condition comparisons and Hering's "Compare" line are relationship sections too, though they describe similarity rather than sequence. When the repertorisation leaves three remedies close together, the Compare lists are the quickest route to the sentences that separate them; the materia medica versus repertory guide describes that hand-off.
A question that comes up constantly, whether two remedies can be given together, is answered by the tables' own existence. The classical method described in the Organon gives one remedy at a time, and the relationship tables exist to sequence remedies, not to combine them. Alternation and combination are separate, debated practices. Nothing here is guidance on taking remedies; that conversation belongs with the prescribing practitioner.
Relationships in the repertory
Repertories carry relationships in two forms, and neither is a rubric. Boenninghausen's Therapeutic Pocketbook includes concordances: for each remedy, the medicines observed to relate to it. Boger carried the idea into the BBCR, and our Boenninghausen guide, linked above, describes those concordances as a practical tool for the second prescription. Knerr's repertory of Hering's Guiding Symptoms, one of the seven classical repertories in Similia Free, carries Hering's relationship material as well, which is why Knerr is one of the sources behind Similia's Relationships view.
The distinction is the question being asked. A rubric answers "which remedies produce or cure this symptom?" A concordance answers "given that remedy A has acted, which remedies relate to it?" The first is consulted while building the case, the second after a remedy has been given; confusing them produces a repertorisation weighted by a remedy's friends rather than by the patient's symptoms.
Where to read relationships on Similia (free reader and Pro view)
The relationship sections quoted throughout this article are readable free on Similia's public materia medica pages: Boericke's Relationship line, Clarke's Relations, Hering's section 48, H. C. Allen's Relations, and the lecture passages in Farrington, Nash and Hahnemann. Similia Free includes 21 classic materia medica books to read online, and reading a remedy's relationship section on its page needs no account at all. The seven classical repertories come with AI semantic search; searching the materia medica itself requires paid access.
The in-app Relationships view is a Pro feature. It gathers the relationship notes for the remedy you are reading from Clarke, Boericke, Knerr, Phatak and Pitt into eight groups: Complementary, Follows well, Followed well by, Compare, Compare collateral, Antidotes, Antidoted by and Inimical, with each entry keeping its source and a per-source toggle in Settings. The Pitt entries come from Richard Pitt's Comparative Materia Medica, part of the separately purchased Richard Pitt Package. The guide to exploring remedy relationships walks through the view step by step, and the Free versus Pro comparison sets out what each plan includes.
Start with one remedy
Pick one polychrest you prescribe often. Open its Relationship line in Boericke and its Relations paragraph in Clarke side by side, and write down where they disagree: a complement one lists and the other omits, an inimical pair only one records, an antidote Clarke explains and Boericke had no room for. Then open Hering's section 48 for the same remedy and see which of the two he agrees with. An hour of this teaches more about how the tables were built, and how much weight each entry can bear, than any chart. It is the habit that turns a relationship note from a rule back into what it always was: one named author's observation, offered for you to test against your own cases.
