Rose water - the history
Made from the steam distillation of rose petals, rose water - which usually contains 10-50% rose oil by weight - has a reputation for having antiseptic and antimicrobial properties. It is reported that it takes 50,000 petals to create just one ounce of pure rose oil. In the Middle East and Asia, rose water is a popular treatment for acne, and Indians have also used rose water as a facial cleaner for centuries.
Rose water - today
Today, science seems to have quite a few studies that support the theories behind using rose water to treat acne. Inflammation is the number one cause of acne, and studies from 2013 and 2004 appear to show that rose oil has very effective anti-inflammatory properties, with the former concluding "our results indicate that rose geranium essential oil may have significant potential for the development of novel anti-inflammatory drugs".
These studies also had another exciting discovery. Along with its anti-inflammatory effect, the topical application of rose oil to the skin reduced the immune system chemicals called neutrophils. Neutrophils, a type of white blood cell, while they mean well, can be a cause behind the development of acne. Rose oil was also found to be very effective at killing bacteria, although P. Acnes were not included in the study.
Anything to worry about?
Geraniol, the main ingredient in rose water, is known to be potentially very irritating to the eyes (although Indian women have used it for centuries). Other than that, unlike other essential oils and waters like tea tree, rose water is not known to cause any negative skin side effects. What should be kept in mind, however, is that rose water has not yet been tested on patients with acne or on P. Acnes bacteria, so it might be worth waiting it out and seeing what the science says.