One property of geranium essential oil may be the ability to help prevent allergic reactions. A preclinical study showed that geranium oil inhibited the degranulation of mast cells. Mast cells are a type of immune cell involved in the inflammatory allergic response, and degranulation is one of the steps in the allergic response. Citronellol, the main phytochemical in geranium oil, was also able to prevent mast cells from producing tumour necrosis factor-alpha (TNF-a) during exposure to antibodies. TNF-a is an inflammatory substance with often destructive effects. Another primary component of geranium essential oil is geraniol. While it cannot reduce TNF-a production according to one study, it was able to increase production of an anti-inflammatory substance known as interleukin-10.
|Pretty P. graveolens. Source: Allgau|
Geranium oil may even be a useful ingredient in natural tick repellents, well, if one of the ticks in your area is Amblyomma americanum (the lone star tick). Certain components of P. graveolens essential oil were able to repel this species of tick up to a success rate of 90%! The most effective was 10-epi-gamma-Eudesmol, which was comparable to DEET when tested. However, it may be best to use geranium as a part of your tick repellent recipe, instead of replacing the other ingredients that already work for you.
Finally, geranium essential oil could even be used to control mites in the home, if the species Dermatophagoides farinae and D. pteronyssinus are common where you live. Interesting Latin fact: "Dermatophagoides" means something along the lines of "skin eater", but this would only be dead skin that's already fallen off you. The most effective components of geranium essential oil were geraniol and beta-citronellol; they were even more effective than DEET!
Overall, many essential oils such as geranium have many uses, it all depends on what is best for you and your home on an individual basis.