Definition
A decoction is a liquid preparation made by boiling a substance — typically a plant, root, bark, or other organic material — in water to extract its soluble properties. The term carries two related meanings in legal contexts: (1) the process of boiling a substance in water for the purpose of extracting its active constituents, and (2) the resulting liquid itself, being water impregnated with the principles drawn out of the boiled material.
The term appears almost exclusively in criminal law sources in connection with prosecutions for poisoning or unlawful administration of noxious substances. Its legal significance is narrow: courts and authorities have treated "decoction" and "infusion" as terms of the same genus (ejusdem generis), meaning that an indictment charging the administration of a decoction is not fatally defective if the evidence shows an infusion was administered instead, and vice versa. The variance is considered immaterial because both are liquid preparations derived from organic substances and differ only in method of preparation — boiling versus steeping.
Common Language
Modern common usage (Wiktionary): An extraction or essence of something obtained by boiling it down; also the process of boiling something down in this way.
Historical common usage (Webster's 1913): The act or process of boiling anything in a watery fluid to extract its virtues; an extract obtained by boiling a body in water. Distinguished in pharmacy from infusion, where there is merely steeping without heat.
The common and legal meanings here are essentially the same in substance — the legal definitions in Black's and Bouvier's both track Webster's closely. The legal significance lies not in any divergence from the common meaning, but in where the word lands inside a criminal indictment and what consequences follow from pleading it rather than its near-synonym, infusion.
Common Confusion
Decoction vs. Infusion: The two terms are pharmacologically distinct — a decoction requires boiling, an infusion requires only steeping in liquid. Historically, both prosecutors and defense counsel treated this distinction as potentially decisive in poisoning cases. The English courts resolved the tension by ruling the terms ejusdem generis, making any variance between them immaterial to the indictment. Researchers should not assume that modern pleading liberality applies to older cases; the rule resolving this particular variance was itself a point of live litigation, as illustrated in the Bouvier's entry referencing the savin-shrub case.
Why It Matters in Research
This term is essentially confined to a single corner of the historical corpus: criminal poisoning prosecutions, primarily from the eighteenth and nineteenth centuries. Researchers will encounter it in indictment forms, trial records, and early pharmacological-legal commentary rather than in modern statutes or contemporary doctrine.
Several navigational points deserve attention:
First, the ejusdem generis ruling on decoction and infusion is the entire reason the term carries legal significance at all. If you are tracing pleading requirements in historical poisoning prosecutions, this is the operative principle — not any pharmacological distinction between the preparations.
Second, Black's 2nd Edition cites Sykes v. Magone (C.C., 38 Fed. 497) in connection with this term. That citation appears in the context of customs classification of imported goods, suggesting the word surfaced in commercial and regulatory law as well as criminal law — specifically in disputes over how to classify liquid botanical preparations for tariff purposes. Researchers working in customs history should note this secondary usage.
Third, historical medical-legal texts will use "decoction" in a purely descriptive sense when cataloguing alleged poisons, remedies, or abortifacients. The savin-shrub case referenced in Bouvier's involves a decoction allegedly used to procure a miscarriage — a recurring fact pattern in nineteenth-century criminal cases. Researchers should be alert to the overlap between poisoning law and abortion law in this era, where the substance administered and its method of preparation could affect the charge and its proof.
Fourth, the term will not appear in modern American statutory or case law in any legally operative sense. If it appears in contemporary sources, it is almost certainly in a historical, pharmacological, or regulatory context (e.g., herbal supplement classification) rather than as a term of art.
Historical Dictionary Support
All three source dictionaries — Black's (1st and 2nd Ed.) and Bouvier's — are in agreement on the core definition, each tracking Webster's pharmaceutical meaning closely. The convergence is unsurprising: this is a term borrowed wholesale from pharmacy, not one that developed independent legal content.
Bouvier's adds the most texture by narrating the underlying case (the savin-shrub indictment) and noting that defense counsel argued the variance between decoction and infusion as grounds for acquittal — an argument the court rejected. Black's 2nd Edition adds the Sykes v. Magone citation, which Bouvier's and the 1st Edition omit, and which points toward the customs classification dimension of the term.
What the historical dictionaries do not address: any modern regulatory meaning, any statutory definition, or any application outside criminal and customs contexts. Their silence on those fronts accurately reflects the term's legal footprint — narrow, archaic, and historically bounded.
Jurisdictional Note
The ejusdem generis rule treating decoction and infusion as interchangeable for indictment purposes originates in English common law and was carried into early American practice. No significant modern American jurisdictional variation exists because the term has effectively left operative legal usage.