Personal Defense Spray

Pepper spray, also known as OC spray (from "Oleoresin Capsicum"), OC gas, and capsicum spray, is a lachrymatory agent (a chemical compound that irritates the eyes to cause tears, pain, and even temporary blindness) that is used for personal self-defense, including defense against dogs and bears. The active ingredient in pepper spray is capsaicin, which is a chemical derived from the fruit of plants in the Capsicum genus, including chilis.

Extraction of oleoresin capsicum from peppers involves finely ground capsicum, then the capsaicin is extracted in an organic solvent such as ethanol. The solvent is then evaporated, and the remaining waxlike resin is the oleoresin capsicum. An emulsifier such as propylene glycol is used to suspend the OC in water, and pressurized to make it aerosol in pepper spray. The high performance liquid chromatography (HPLC) method is used to measure the amount of capsaicin within pepper sprays. Scoville Heat Units (SHU) are used to measure the concentration or "heat" of pepper spray.

Oleoresin capsicum also is used in foods where the flavor and piquancy are desired without visible pepper specks, or to standardize the Scoville units.

Pepper spray is an inflammatory. It causes immediate closing of the eyes, difficulty breathing, runny nose, and coughing. The duration of its effects depend on the strength of the spray but the average full effect lasts around thirty to forty-five minutes, with diminished effects lasting for hours. The Journal of Investigative Ophthalmology and Visual Science published a study that concluded that single exposure of the eye to OC is harmless, but repeated exposure can result in long-lasting changes in corneal sensitivity. They found no lasting decrease in visual acuity.