Arnica montana commonly interacts with which type of medications?

• A. Antibiotics
• B. Antivirals
• C. Anticoagulants and antiplatelets
• D. Antihistamines

Answer: (C)

Arnica montana can interact with blood-thinning medications because it may affect coagulation and platelet function, increasing the risk of bleeding. Compounds in arnica, such as sesquiterpene lactones, contribute anti-inflammatory effects but can influence the coagulation system or platelet activity when taken with anticoagulants or antiplatelet drugs. Because of this potential additive effect on bleeding, avoid internal use of arnica or use it only under professional guidance if you’re taking these medications. The other drug classes listed (antibiotics, antivirals, antihistamines) don’t have a well-established, consistent interaction with arnica in standard teaching, so they’re not the typical concern here. Topical arnica is generally safer but still warrants caution in those on blood-thinning therapy.