Pyrrolizidine Alkaloids in Healing Herbs

Borage ~ Borago officinalis

Folks continue to ask about the safety of PA alkaloids (pyrrolizidine alkaloids) that are found in many healing herbs such as boneset, borage, coltsfoot and comfrey. Point-by-point, here are things to consider:

1) No viable animal testing was done with any PA containing herbs on primates therefore there is no cause for fear in using these herbs on humans.

2) No viable testing was done at all. The studies done have had serious flaws, such as using amounts of the herbs that would far exceed even accidental over-use, and using the PA's only extracted from the plant material in a lab, which few herb users would have access to or be likely to do. Herbs wisely contain many buffering agents to their more potent constituents. This is why we always use herbs in their natural, intact state, not standardized to concentrate some constituents and not others, and not just one constituent from a whole plant.


3) PA's are metabolized through the liver, and have been implicated in liver trouble *in people whose liver health was unknown before ingestion*. So logic prevailing: don't use herbs containing PA's if you already have liver problems, or if you take anything else that might compromise liver health, such as taking NSAIDs (Nonsteroidal Antiinflammatory Drugs, like aspirin or Ibuprofen ) or most pharmaceutical medications, just to be safe. PA alkaloid containing herbs, chemotherapy and stem-cell transplant have all been implicated in Veno-occlusive disease. If you have Veno-occlusive disease already, are using a form of chemotherapy or have had a stem cell transplant, don't use herbs that contain PA alkaloids.  

Comfrey ~ Symphytum

4) Make sure the herb is correctly identified. Foxglove leaves look allot like small comfrey leaves. This mistake can be deadly and has nothing to do with PA's.


Also, As trained herbalists we learn how to harvest and prepare herbs for best effects. Herbs with PA alkaloids traditionally are harvested and extracted in ways that would avoid the peak of concentration and extraction of PA's. They are more plentiful in annual herbs than perennial, more plentiful in the roots than in the leaves. This is why we don't see borage root used in herbal tradition and it is usually the perennial leaves that are used instead. PA's are used in the process of blooming and so this is why we harvest these herbs for use while they are blooming, while flowers are on the plant or any time after. Another way to obtain lower PA's is that we know that PA's are not very water soluble, and so drying these herbs and making herbal infusions is traditionally how they are used. Tinctures of these herbs are made from fresh plant material, using low alcohol content, such as 40%  alcohol, which is 80 proof .The resultant tincture tends to be 30-35% alcohol in its finished state, depending on juiciness of the herb. If you follow both science and tradition it is evident that they often confirm and validate each other, especially when it comes to using herbs that contain PA alkaloids.

Coltsfoot~ Tussilago farfara

5) Use time tested applications for herbs high in PA's. Many of these herbs have been used for hundreds of thousands of years with good results. These are herbs that are seldom used as tonics, except in specific circumstances and only with people who actually need them. They are not to be harvested, extracted or used casually or carelessly. Learn how they were and are used, how much to use, and with what health concerns to use them. This takes plenty of study and is well worth the time.



To quote Paracelsus "Poison is in everything, and no thing is without poison. The dosage makes it either a poison or a remedy."



6) If you are not confident in using these herbs yourself but feel they may be helpful to you, consult an herbalist who is more experienced in their use, as your guide.

7) Education is the solution to fear, not restriction and regulation.

Here is a link for detailed study: Gerneral Information about Pyrrolizidine Alkaloids