What Are the Potential Side Effects of Harpagophytum (Devil's Claw)?

Harpagophytum, commonly known as devil's claw, is a tuberous perennial herbaceous plant of the genus Harpagophytum in the Pedaliaceae family. This plant, which has only recently become known in the West, originates from the desert regions of southern Africa: the steppes of Namibia, the Kalahari Desert, and southern Africa. Harpagophytum, Harpagophytum procumbens, derives its name from the Greek phyton, "plant," and harpagos, "harpoon." This is the origin of the term devil's claw, as its harpoon-shaped fruits with sharp hooks attach themselves to the fur of animals such as sheep and cattle, and to the hooves of antelopes, all of which thrash about frantically to rid themselves of them as if they had "the devil in their bodies." It is a strategy, successful to say the least, for dispersing its seeds. As for procumbens, it is derived from the Latin procubo, meaning "to lie prone, stretched out." Indeed, its stem is creeping and can spread up to 2m in length. It bears alternate leaves with ovate blades as well as solitary, ephemeral, red-violet, trumpet-shaped flowers that bloom for only a single day. The fruit is a woody capsule with a crown adorned with several sharp hooks, the famous devil's claw.

Its main, woody root burrows vertically up to 1m into clay or sandy soil. From this main root, several secondary roots branch out, forming bulbous storage tubers, sometimes very large, weighing up to 1.5kg, found as deep as 2m. These serve as a reserve of water and nutrients for the plant, enabling it to withstand periods of drought. These tubers reach a size of 4 to 6cm in diameter and 15 to 25cm in length after 3 to 4 years, at which point they are harvested. Indeed, only these tubers (which constitute up to 90% of the plant's weight) are used in traditional medicine in southern Africa and in our pharmaceutical industry.

The medicinal potential of Harpagophytum became widely known in the Western world in the 1970s and 1980s. A victim of its own success, Harpagophytum became an endangered species in the early 2000s. Today, devil's claw enjoys protected status that regulates its harvesting, but it remains vulnerable. Various cultivation trials are underway, yet devil's claw remains difficult to grow.

Harpagophytum is primarily used for all types of osteoarticular pain.

• Lower back pain: back pain, lumbago, neuralgia, sciatica

• Joint pain: arthritis, rheumatoid arthritis, osteoarthritis

• Muscle pain: Tendinitis, sprains, strains

• Reduction of gout symptoms: Thanks to its anti-inflammatory properties, harpagophytum can help relieve gout symptoms by reducing inflammation and pain

• For painful periods.

Harpagophytum can cause side effects and interact with many medications. The following have been reported in particular:

• Gastrointestinal issues: diarrhea, nausea, vomiting, abdominal pain, as well as increased stomach acidity. In the latter case, caution is advised when using antacids.

• An increased risk of bleeding when Devil’s Claw is taken with anticoagulants or nonsteroidal anti-inflammatory drugs.

• Harpagophytum can significantly alter the concentration or action of medications, particularly with hypoglycemic agents.

• When combined with certain antihypertensives, Harpagophytum enhances the antihypertensive effect and consequently causes hypotension.

• Harpagophytum may alter the rhythm and strength of heart contractions; therefore, extreme caution is recommended in patients taking antiarrhythmics or digitalis-based medications.

• Caution is also advised in cases of renal insufficiency.

• Nervous system disorders: headaches, dizziness

• Allergic reactions: skin reactions (red patches, hives); edema, particularly facial.

For all forms of Devil’s Claw—whether as a dry extract or a fluid extract—it is generally recommended not to exceed 6g of Harpagophytum per day. However, this depends on the concentration of the plant’s active ingredient; therefore, it is essential to follow the dosage recommended by the manufacturer. 

Courses of 3 to 4 weeks are generally recommended, to be repeated for osteoporosis, joint flexibility, and osteoarthritis. For other conditions, Harpagophytum should be taken during the period of pain, not exceeding 4 weeks. It is best to alternate with other herbs in cases of chronic pain to avoid side effects and tolerance to the active compounds.

To address the numerous contraindications, side effects, and precautions associated with Harpagophytum as an anti-inflammatory and pain reliever, the following plants and dietary supplements can be used:

1. Turmeric is recognised as an excellent anti-inflammatory and pain reliever. What’s more, it protects cartilage; when combined with black pepper, it effectively combats inflammatory diseases.

2. Fresh ginger is a remarkable anti-inflammatory that can be easily incorporated into diet and juice blends, offering benefits for all types of inflammatory conditions.

3. Boswellia or indian frankincense (also known as Boswellia serrata): is a remarkable anti-inflammatory

4. Ash is a remarkable anti-inflammatory and analgesic, used in particular for joint pain and gout

5. White Willow contains acetylsalicylic acid, a precursor to aspirin, a well-known anti-inflammatory

6. Arnica is a plant used both for bruises and for acute or chronic pain such as rheumatism. Just like Harpagophytum, mountain arnica suffers from its own popularity.

7. Daisy is a small, very common plant whose analgesic and anti-inflammatory effects are less well known. It is a very interesting alternative to mountain arnica.

8. The oil macerate of St. John's Wort is a very good anti-inflammatory used on painful areas of the body.

9. Collagen strengthens cartilage and offers real benefits for the joint system; it is a beneficial supplement for preventing joint-related problems.

Although Harpagophytum is generally well-tolerated, it can cause side effects in some people, such as gastrointestinal issues (nausea, diarrhea) or allergic reactions. People with specific medical conditions, such as stomach ulcers, or those taking medications, should consult their doctor before using Harpagophytum.

Although Harpagophytum is a remarkable plant, it does carry side effects that other, more commonly used plants don't. It's best used occasionally rather than long-term, both to limit the risk of side effects and to help preserve the resources that indigenous peoples are entitled to benefit from.

Catherine is passionate about plants and their properties. She studied natural cosmetics at the École Lyonnaise des Plantes Médicinales in the early 2000s. Driven by curiosity, she has continued to explore the richness and potential of plants. This led her to train in aromatherapy at the École Française d’Aromathérapie Intégrative. She discovered an almost unexplored world in olfactotherapy, and valuable tools for getting to know herself better and practising what she calls inner ecology.