[Recommendations of the DGRh Committee on Complementary Medicine and Nutrition on the application of selected phytotherapeutic drugs and herbal medicines in rheumatology].

Background: Herbal preparations and phytotherapeutic substances are offered for symptoms and diseases of the rheumatic spectrum and are often intensively advertised in the lay press. The German Society for Rheumatology and Clinical Immunology (DGRh) Committee on Complementary Medicine and Nutrition reviewed the scientific literature on selected over the counter preparations and prescription phytotherapeutic substances and examined the possibilities for their use in rheumatology.

Methods: In an online meeting of the Committee on 8 February 2023 a list of herbal preparations that are frequently used in rheumatology (mostly as self-medication) was drawn up. Each member of the committee then carried out a literature search on one or two substances and summarized the results according to a defined matrix. Research was carried out on borage oil, stinging nettle preparations, cannabis preparations and preparations of dog rose, rosemary, saffron and willow bark. The data on the mixed preparation Phytodolor® (Bayer Vital GmbH, Germany) were also examined. The results were reviewed by a circulation procedure and approved in two further online meetings of the Committee. After review by the DGRh board, the recommendations were transferred to the professional organization's website.

Results: Even though there are reports of anti-inflammatory or immunological effects in vitro and/or in animal models for all the plant substances examined, the evidence for a clinically relevant benefit is sparse. None of the preparations investigated has a therapeutic efficacy that justifies its use in inflammatory joint diseases. Herbal preparations based on saffron and rosemary are generally not recommended. Borage oil from seeds can be taken in standardized form as part of a health-conscious diet but is not expected to have any significant anti-inflammatory effect. Rheumatologists need not advise against Phytodolor® or preparations based on stinging nettle, willow bark or dog rose, which are taken on the patient's initiative for degenerative joint diseases, if a sensible therapy concept is otherwise adhered to. There is insufficient evidence to prescribe medicinal cannabis for inflammatory rheumatic diseases for disease modification or symptomatic therapy. In individual cases, however, its use to reduce chronic pain, particularly neuropathic pain and sleep disorders and to reduce opiate consumption may be justified.

Conclusion: Even if the herbal preparations presented here must be considered in a differentiated manner for rheumatology practice, the value of phytotherapy for the discipline is low.