Can calendula macerate eliminate warts?

Plantar, genital, flat, common... Cutaneous warts are small benign growths that vary in shape, colour, and size, depending on their location and the type of virus involved. They result from an infection of the epithelial cells in the basal layer by one of the many types of Human Papillomavirus (HPV), a virus with cutaneous or mucosal tropism. Once the virus is introduced into the epidermis, usually through a micro-lesion, it stimulates the proliferation of keratinocytes, leading to a thickening of the skin. Although warts can appear on any part of the body, they preferentially develop on areas exposed to friction, such as the face, hands, and feet. These locations not only favour their appearance but also their transmission, particularly in humid environments like swimming pools or changing rooms.

Good to know: Plantar warts are often confused with corns. To distinguish them, know that the former are often painful and allow blood vessels to show through, unlike the latter.

When it comes to managing warts, the usual approach is cryotherapy, using liquid nitrogen, or with wart removers, such as salicylic acid. However, alternative techniques are emerging, such as the use of calendula macerate. Primarily known for its soothing and healing properties, it is gradually making a name for itself as a natural solution to warts, and is notably used in the Marigold Clinic of the Royal London Homeopathic Hospital, specialising in the treatment of chronic foot conditions and sports injuries to the feet.

The marigold therapy, another name for calendula, is a two-step process in the case of warts: the patient is seen once a week by a podiatrist for about four weeks. A marigold poultice is applied with a protective pad at each session. The follow-up treatment then involves the daily application of calendula oil. According to a scientist from the clinic team, four to six sessions of marigold therapy could completely eliminate or significantly reduce warts. However, no information has been communicated about the mode of action by which the calendula macerate would work.

Some sources suggest that calendula could eliminate warts through its antibacterial and antifungal activities. However, this explanation is not entirely satisfactory. Indeed, antibacterials and antifungals target bacteria and fungi respectively by disrupting biological mechanisms specific to these microorganisms. For instance, antibiotics can prevent the synthesis of the bacterial wall or block the replication of bacterial DNA, while antifungals alter the cell membranes of fungi by targeting ergosterol, a component absent from human and viral cells. Viruses operate in a completely different manner: they possess neither a cell wall nor their own metabolism, and they replicate solely by hijacking the mechanisms of host cells. As warts are caused by viruses, the potential effect of calendula on these skin growths cannot be explained by its antibacterial and antifungal properties.

The marigold macerate could potentially play a role in the management of warts but the scientific evidence remains limited in the absence of clinical studies and hypotheses regarding its mechanism of action. Therefore, further research is necessary to confirm its effectiveness.

• ROE N. & al. Auditing marigold therapy as a first-line treatment for plantar corns and verrucae pedis. Podiatry Now (2009).

• HOROWITZ S. Innovative Therapies in Podiatry and Physical Medicine. Alternative and Complementary Therapies (2010).

• NIGAM P. S. & al. Antimicrobial activity of Calendula officinalis petal extracts against fungi, as well as Gram-negative and Gram-positive clinical pathogens. Complementary Therapies in Clinical Practice (2012).

• GUPTA S. K. & al. Therapeutic Potential of Calendula officinalis. Pharmacy & Pharmacology International Journal (2018).