Though it is sometimes used by herbalists or people seeking natural alternatives to everyday chemical-filled medication, arnica montana can result in many negative side effects that outweigh its potential benefits. Overall, it is a risky herb to use and should be avoided if possible unless it is very slowly introduced to the body and confirmed to be safe for each individual case.
Blood Thinner
This may be a good effect if one’s blood is excessively thick, clotting unnecessarily. For those who have blood of normal thickness (or people who already have thin blood) it can be extremely dangerous. Thin blood can result in uncontrollable bleeding from even the slightest of wounds. Common medications with blood thinning or similar properties like coumadin, aspirin, and clopidogrel can interact poorly with arnica montana.
Epistaxis
Combined with the effect of thinning blood, epistaxis (bleeding from the nose) can become quite dangerous. The nose may be unable to clot, and blood could pool internally or continuously pour from the nose. For those who are fortunate enough to not experience blood thinning from the herb, the nosebleeds may not prove to be much of an issue.
Anaphylaxis and Other Reactions
Daisies and other plants in the same family share the same components that invoke allergic reactions as arnica montana. It is possible that simple rashes or irritation could result from an allergic reaction, but one could also enter anaphylactic shock.
Severe Dizziness
Lightheadedness and debilitating dizziness are both possible arnica montana side effects. In the case of chronic loss of balance or the sensation that the room is moving (not just from visual confusion) could be a sign of a much more severe issue, so be sure to report this immediately.
Stomach Trouble
When this herb is eaten or consumed in the form of a tea, it has been known to cause extreme stomach discomfort and long term loss of appetite. The herb irritates the lining of the digestive tract, and in higher doses it could cause lasting damage. It can also cause nausea and vomiting.
Strong Laxative
Again, while this might be a benefit in extreme cases of constipation, most users will see this as one of the most uncomfortable arnica montana side effects. It is not a safe laxative, in that the reason it loosens stool lies in the body’s attempt to compensate for having an alien substance in its system. As such, it could become a lasting problem, resulting in regular diarrhea.
Heart Arrhythmia
The American Cancer Society has published a statement informing the public that arnica can potentially cause a heart arrhythmia. This is an irregular rate of beating for the heart, resulting in too much or too little blood flow that can result in a variety of dangerous outcomes. Sluggishness, chronic fatigue, dizziness, and fainting can all be warning signs of an arrhythmia. It is an easily detected condition, so be sure to mention it to your doctor if any of these are experienced (and of course immediately cease consuming arnica).
Uncontrollable Shaking
Colloquially referred to as tremors, chronic slight shaking of the hands, legs, arms, or head can result from taking arnica supplements or eating the herb. This is a result of the central nervous system responding negatively to the presence of the herb in the body. Consult a doctor immediately for a health assessment and advice on how to proceed.
Health Benefits
Despite all of the negative arnica montana side effects, it can be legitimately used for some things. This list includes topical application for sunburns and bruises (which carries far less risk than consuming it). It may also be an effective antibacterial agent, though one should never use it on any cuts, sores, scabs or blisters that may become open wounds; direct absorption of a concentrated ointment into the bloodstream is the worst possible scenario when using arnica.
Joxito