Geranium wilfordii Side Effects and Contraindications
May 13, 2025
Source: Cainiu Health
Dr. Yu Yongchao
Introduction
Geranium wilfordii (Wild Geranium) is a common weed with palmately divided leaves and small淡purple or white flowers. It commonly grows on hillsides and along roadsides in northern China. People use the entire plant, dried and processed for medicinal purposes, either steeped in hot water or crushed and applied externally. It can help alleviate rheumatic joint pain, muscle soreness, and minor skin inflammation with redness and swelling.
Generally, the side effects of Geranium (Lao Guan Cao) include gastrointestinal irritation, allergic reactions, hepatotoxicity, renal tubular injury, and abnormal coagulation function. Contraindications include pregnancy, bleeding disorders, autoimmune diseases, peptic ulcer and gastritis, and hyperthyroidism. Details are as follows:
I. Side Effects
1. Gastrointestinal Irritation: Geranium contains high levels of tannins, which can constrict mucosal blood vessels in the gastrointestinal tract and inhibit secretion of digestive fluids, leading to mucosal dryness and inflammation. The volatile oils can directly stimulate intestinal smooth muscle, causing spasms.
2. Allergic Reactions: Flavonoids and volatile oils contained in Geranium can act as allergens, triggering IgE-mediated hypersensitivity reactions. These may lead to contact dermatitis, allergic rhinitis, or asthma.
3. Hepatotoxicity: Terpenoid components in Geranium must be metabolized by the liver; excessive amounts may overload cytochrome enzymes, leading to hepatocyte necrosis. This may manifest as elevated transaminases, jaundice, fatigue, and other symptoms.
4. Renal Tubular Injury: Metabolites of tannins in Geranium bind to renal tubular epithelial cells, inducing oxidative stress damage. Some alkaloids may directly damage nephrons. Manifestations may include reduced urine output, hematuria, and elevated creatinine levels.
5. Abnormal Coagulation Function: Coumarin derivatives in Geranium, such as umbelliferone, can inhibit vitamin K epoxide reductase, thereby interfering with coagulation function. This may lead to subcutaneous bruising, nosebleeds, and increased menstrual flow.
II. Contraindications
1. Pregnant Women: Volatile oil components in Geranium, such as α-pinene, have uterine-stimulating effects and may induce contractions, leading to miscarriage. It is contraindicated for women planning pregnancy or in early pregnancy.
2. Patients with Bleeding Disorders: Coumarin derivatives inhibit vitamin K epoxide reductase and the synthesis of coagulation factors. By impairing coagulation factors and platelet function, they may exacerbate bleeding tendencies.
3. Patients with Autoimmune Diseases: For example, in rheumatoid arthritis, polysaccharide components in Geranium may overactivate helper T-cell immune pathways, worsening autoimmune responses.
4. Patients with Peptic Ulcer and Gastritis: Tannins combine with gastric mucosal proteins to form insoluble complexes, disrupting the mucosal barrier. Volatile oils stimulate gastric acid secretion. Use cautiously in patients with active ulcers.
5. Patients with Hyperthyroidism: Geranium has a relatively high iodine content; long-term use may interfere with thyroid hormone synthesis, inducing hyperthyroidism. It may still pose a risk for patients already suffering from hyperthyroidism.
The side effects and contraindications of Geranium are usually related to its plant components and individual physical conditions. If a scientific medication plan is required, it is recommended to adjust the treatment regimen under the guidance of a TCM physician according to the patient's constitution.
