Materia Medica

Poppy Seed (Papaver somniferum) — Opium Poppy, Breadseed Poppy
A safety-focused guide to poppy seed (Papaver somniferum), separating ordinary culinary seeds from opium latex and unwashed residue-laden products while covering alkaloid contamination, drug testing, legal context, pregnancy, allergy and overdose risks. Read more...
Prickly Ash (Zanthoxylum americanum) — Northern Prickly Ash, Toothache Tree
A research-grounded guide to northern prickly ash (Zanthoxylum americanum), covering toothache-tree history, bark and berry use, pungent alkylamide chemistry, evidence limits, pregnancy cautions, species confusion and responsible sourcing. Read more...
Pumpkin Seed (Cucurbita pepo) — Pepitas, Field Pumpkin
A research-grounded guide to pumpkin seed / pepitas (Cucurbita pepo), separating food seeds from oil and concentrated extracts while covering nutrition, lower urinary tract and prostate research, evidence limits, allergy, pregnancy and safety. Read more...
Purslane (Portulaca oleracea) — Pigweed, Little Hogweed, Verdolaga
A research-grounded guide to purslane (Portulaca oleracea), covering food use, ALA omega-3s, oxalates, emerging metabolic research, safe wild identification, spurge look-alikes, pregnancy and harvest safety. Read more...
Psyllium (Plantago ovata) — Ispaghula, Blonde Psyllium
Psyllium, also called ispaghula or blond psyllium, comes from Plantago ovata. Its husk is a highly water-absorbing, gel-forming soluble fiber widely used for bowel regularity. This guide separates seed from husk, reviews evidence for constipation, cholesterol and blood-sugar support, and explains crucial fluid, swallowing, allergy and medication precautions. Read more...
Quince (Cydonia oblonga) — Quince Apple, Cydonia
Quince (Cydonia oblonga) is an aromatic Rosaceae fruit with a long culinary and traditional-medicine history. This guide separates ordinary quince fruit from leaves, concentrated extracts and seed preparations; reviews the limited human research on reflux and nausea; and explains why quince seeds and cyanogenic compounds deserve separate safety attention. Read more...
Ragwort (Jacobaea vulgaris) — Tansy Ragwort, Stinking Willie, Benweed
Tansy ragwort, also called common ragwort, is Jacobaea vulgaris (formerly widely known as Senecio jacobaea). This is a toxicity and identification article: the plant contains unsaturated pyrrolizidine alkaloids associated with serious liver injury in people and livestock. No medicinal dosing or preparation instructions are provided. Read more...
Red Root (Ceanothus americanus) — New Jersey Tea, Mountain Sweet
Red root or New Jersey tea (Ceanothus americanus) is a native North American shrub with a Revolutionary-era leaf-tea history and a separate medicinal root tradition. This full guide covers Indigenous and American herbal history, leaf-versus-root preparation, ceanothane triterpenes, lymphatic and spleen traditions, sustainability, growing, harvesting and safety. Read more...
Reishi / Lingzhi (Ganoderma sichuanense) fruiting bodies
Reishi (Ganoderma lingzhi) — Lingzhi, Mushroom of Immortality
Reishi or lingzhi is the famous East Asian medicinal mushroom now best identified in its widely cultivated Chinese lineage as Ganoderma sichuanense, with G. lingzhi still common as a synonym... Read more...
Rhodiola (Rhodiola rosea) — Roseroot, Golden Root, Arctic Root
Rhodiola / roseroot (Rhodiola rosea) is a cold-climate root herb traditionally associated with fatigue, endurance and resilience. This full guide covers traditional tea and extracts, rosavins and salidroside, stress and fatigue research, mood and exercise evidence, product authenticity, medication cautions, cultivation, CITES trade controls and sustainable sourcing. Read more...
Original botanical visualization of Rheum palmatum Chinese rhubarb, large lobed leaves and branched flower clusters in bright mountain meadow
Chinese Rhubarb (Rheum palmatum) — Turkey Rhubarb, Indian Rhubarb
Chinese rhubarb root, called Da Huang in Chinese medicine, is primarily associated in modern European herbal regulation with short-term stimulant-laxative use for occasional constipation. This guide separates medicinal Rheum palmatum... Read more...
Rooibos (Aspalathus linearis) — Red Bush, South African Red Tea
Rooibos / red bush (Aspalathus linearis) is South Africa’s naturally caffeine-free herbal tea. This full guide covers Khoi and San traditional knowledge, practical brewing, red versus green rooibos, aspalathin and other flavonoids, human research, rare safety concerns, cultivation, sustainability and ethical sourcing. Read more...