The Herbal Reference Library
Evidence-informed guides to herbal combinations, formulation, medication interactions, plant monographs, and building a practical herbal reference library.
Herbs Not to Mix With Medication: A Practical Guide
Natural does not mean interaction-free. These are the herbs most often flagged with medications, and a simple way to check your own list.
Herbs and Diabetes Medication: Interactions to Know
Many herbs sold for blood sugar support can interact with diabetes medicines in either direction. Here is what federal health sources say.
Herbs That Interact With Blood Thinners
Several popular herbs are flagged with blood thinners, and one can make warfarin work less well. Here is what the evidence says about each.
Ashwagandha and Thyroid Medication: What to Know
Ashwagandha is popular for stress and sleep, but it may influence thyroid hormone levels. Here is what to know if you take thyroid medication.
St. John's Wort Drug Interactions: What to Know
St. John's wort has some of the best-documented drug interactions of any herb. Here is which medicines it affects, why, and how to check safely.
Turmeric and Blood Thinners: What the Research Shows
Turmeric and blood thinners is one of the most-searched herb-drug questions. Here is what the evidence actually shows, and what to ask before you combine them.
Best Herbalism Books for a Working Reference Library
A job-based guide to choosing herbalism books, deciding which references deserve shelf space, and combining print books with current online monographs and safety resources.
How to Read an Herbal Monograph
A field-by-field framework for interpreting herbal monographs without confusing traditional use, laboratory findings, clinical evidence, product directions, and safety warnings.
How to Build a Balanced Herbal Formula
A practical framework for turning a list of herbs into a coherent formula with one clear objective, distinct ingredient roles, intentional proportions, compatible preparation, and a documented safety review.
Pharmacokinetic vs. Pharmacodynamic Herb Interactions
A mechanism-focused guide to how herbs may change medication exposure or alter medication effects—and why a plausible mechanism does not automatically establish a clinically meaningful interaction.
Herb–Drug Interactions: A Practical Guide for Herbalists
Herb–drug interactions are not all equal. Learn how pharmacokinetic and pharmacodynamic interactions occur, how to assess the strength of the evidence, and when a combination deserves professional review.
Herbal Synergy: How to Combine Herbs Intentionally
A practical framework for distinguishing true synergy from simple addition, assigning clear roles within a formula, and building combinations with less redundancy and more purpose.
Recently Updated Guides
Guides are re-reviewed as new evidence and reader questions come in.