When a spider bites your skin, the wound turns red or light pink in color and swells slightly. Most spider bites are harmless, but if you're bitten frequently, you may want a repellent. Natural indoor spider repellents aren't as useful as you might think.
Natural repellents typically mention orange oil or some form of garlic, such as garlic powder or garlic juice. Ultrasonic repellents emit a high-pitched frequency that supposedly repels spiders.
According to the Colorado State University Extension, the sale of ultrasonic repellents is prohibited in the state of Colorado. This is because no research or proof backs up the claims that the frequencies repel or control spiders. The same is said of some chemical products and natural repellents containing garlic or orange.
The Environment Health and Safety Department of Princeton University suggests using repellents that contain DEET or Permethrin. These products are proven to repel spiders.