Herbs have one of the highest natural concentrations of antioxidants of any plant-based food, and rosemary is one of the richest sources. Antioxidants may help decrease the inflammation associated with disorders like arthritis. However, scientific research has not yet conclusively determined whether rosemary is effective in treating or preventing inflammation and arthritis. Don't attempt to self-treat any condition with rosemary until you've spoken to your doctor.
Using Rosemary for Arthritis
In 2003, a study published in the "Journal of Rheumatology" reported that rosmarinic acid inhibited the progression of arthritis in laboratory mice. Rosmarinic acid is a phytochemical contained in a number of herbs, including rosemary. The scientists hypothesized that rosmarinic acid supplementation in humans might help treat rheumatoid arthritis, though clinical studies have not supported this theory, and most research on the topic is conducted with rosmarinic acid isolated from plants other than rosemary. In Germany, rosemary oil applied to the skin is approved as an arthritis treatment, but NYU Langone Medical Center points out that medical evidence doesn't confirm this is effective.
Rosemary as an Anti-Inflammatory Agent
A study published in the "Biological & Pharmaceutical Bulletin" in 2001 showed that rosmarinic acid prevented inflammation in mice by inhibiting their immune response to allergens. Another study from a 2004 issue of "Experimental Biology and Medicine" demonstrated that rosmarinic acid extract could decrease seasonal allergy symptoms in adults. Neither study used rosmarinic acid from rosemary, and none have reported that supplementing with rosemary specifically decreases the inflammatory response in humans.
Possible Side Effects
If you choose to take supplemental rosemary to deal with inflammation or arthritis, take no more than the dose recommended by your doctor and the manufacturers. Too much rosemary can cause muscle spasms, vomiting, unconsciousness and fluid buildup in the lungs. You can take rosemary tinctures and dry or fluid extracts internally, but do not consume rosemary oil because it is toxic. Avoid any form of rosemary supplement if you have high blood pressure or a digestive disorder like Crohn's disease. It may cause miscarriage, though the fresh or dried leaves can be used in food without any ill effects.
Potential Drug Interactions
Many Americans with an inflammatory disease like arthritis have another chronic problem such as diabetes or heart disease. The effectiveness of the medication you take for these conditions may be strengthened or weakened by rosemary supplementation. If you're taking drugs to control your blood sugar, anti-coagulants like warfarin or clopidogrel, lithium, a diuretic such as furosemide or an ACE inhibitor to manage your blood pressure, don't take supplemental rosemary. Women using medication that contains estrogen should also avoid rosemary supplements.