Herbs & Botanicals

Tonka Bean (Dipteryx odorata): Coumarin, Fragrance, U.S. Food Law, Traditional Use & Safety
Tonka bean is the intensely fragrant seed of the South American tree Dipteryx odorata and one of the original natural sources of coumarin. This guide reviews its botany, fragrance and traditional uses, explains human coumarin hepatotoxicity, and states the U.S. food restriction accurately: foods containing added coumarin from tonka beans or tonka extract are deemed adulterated. Read more...
Tobacco (Nicotiana tabacum): Ethnobotany, Nicotine Toxicity, Green Tobacco Sickness & Regulation
Nicotiana tabacum is the principal cultivated tobacco species, a culturally important American plant containing highly addictive and potentially toxic nicotine. This guide covers botany and traditional context, nicotine poisoning, green tobacco sickness from skin exposure, the health effects of tobacco use, and current U.S. tobacco-product regulation without providing smoking, curing or nicotine-extraction instructions. Read more...
Thunder God Vine (Tripterygium wilfordii): Rheumatoid Arthritis Research, Toxicity, Fertility & Safety
Thunder god vine, or Lei Gong Teng, has genuine clinical research in rheumatoid arthritis and kidney disease, but it also has one of the narrowest safety margins among commonly discussed medicinal herbs. This guide reviews efficacy evidence alongside reproductive toxicity, liver and kidney injury, lowered blood-cell counts, pregnancy risk, poisonous plant parts and product-quality concerns. Read more...
Tea Tree (Melaleuca alternifolia): Topical Uses, Acne & Fungal Research, Safety & Essential-Oil Toxicity
Tea tree oil is a steam-distilled topical essential oil from Melaleuca alternifolia with human research for acne and some superficial fungal conditions. This guide separates topical evidence from laboratory claims, explains why the oil should not be swallowed, and covers oxidation, contact allergy, storage and the debated endocrine-disruption claim. Read more...
Tarragon (Artemisia dracunculus): French vs. Russian Tarragon, Traditional Use, Research & Safety
Tarragon is a classic culinary Artemisia with distinct French and Russian forms, a long digestive tradition, and limited but real human metabolic research. This guide explains its botany, flavor chemistry, estragole and methyleugenol safety concerns, and why culinary use is different from concentrated extracts and essential oil. Read more...
Tansy (Tanacetum vulgare): Traditional Use, Thujone Toxicity, Identification & Safety
Common tansy is a historic European herb with old culinary, antiparasitic and household uses, but modern internal use is limited by unpredictable essential-oil chemotypes and thujone neurotoxicity. This guide separates true Tanacetum vulgare from tansy ragwort and feverfew, explains U.S. food restrictions, and reviews identification and safety. Read more...
Sumac (Rhus spp.): Culinary Spice, Wild Beverage, Traditional Use, Research & Safety
Sumac is not one single plant. Mediterranean culinary sumac comes mainly from Rhus coriaria, while North American smooth and staghorn sumacs have their own food and ethnobotanical traditions. This guide separates edible Rhus species from poison sumac, reviews modern human metabolic research, and covers identification, preparation and safety. Read more...
Stevia (Stevia rebaudiana): Sweetleaf, Steviol Glycosides, Blood Sugar Research & Safety
Stevia rebaudiana is the South American sweetleaf behind modern steviol-glycoside sweeteners. This guide separates traditional whole-leaf use from high-purity steviol glycosides, explains U.S. regulatory distinctions, reviews human metabolic research, and covers cultivation and safety. Read more...
St. John’s Wort (Hypericum perforatum): Depression Evidence, Drug Interactions, Safety & Traditional Use
St. John’s Wort is one of the best-studied medicinal herbs for mild-to-moderate depression, but also one of the most interaction-prone. This guide reviews the human evidence, hyperforin and hypericin chemistry, CYP/P-glycoprotein drug interactions, photosensitivity, topical traditions, identification and sourcing. Read more...
Spilanthes / Toothache Plant (Acmella oleracea): Spilanthol, Traditional Use, Research & Safety
Spilanthes, now accepted botanically as Acmella oleracea, is the famous toothache plant or jambu whose flowers produce a tingling, numbing and mouth-watering sensation. This guide explains the modern taxonomy, spilanthol chemistry, culinary tradition, pain research and safety without turning a traditional toothache remedy into a substitute for dental care. Read more...
Spearmint (Mentha spicata): Digestion, PCOS Research, Cognition & Safety
Spearmint is a carvone-rich culinary and medicinal mint with a long digestive tradition and several human trials, including research on androgen levels in women with PCOS and standardized extracts for memory and attention. This guide separates ordinary tea from concentrated extracts and essential oil. Read more...
Sorrel (Rumex acetosa): Edible Greens, Traditional Use, Oxalates & Safety
Common or garden sorrel, Rumex acetosa, is a tart perennial green with a long culinary and traditional herbal history. This guide distinguishes it from wood sorrel and Jamaican sorrel, reviews its nutrition and phytochemistry, and explains why oxalate content matters for kidney-stone-prone people. Read more...