Castor oil
Listed as an inert ingredient permitted in EPA minimum risk (FIFRA 25(b)) pesticide products.
Safety around dogs & cats
The refined oil is a benign emollient and does not contain the ricin found in the raw bean, so incidental contact is low risk for dogs and cats. A meaningful ingested amount acts as a laxative and can cause diarrhea, but it is not a toxicity concern at the levels used in repellents.
Moderate confidence. Ratings from ASPCA Animal Poison Control, the Pet Poison Helpline, and published veterinary toxicology. This is general information, not veterinary advice. If your pet is exposed, call your vet or the ASPCA Animal Poison Control Center at (888) 426-4435.
The evidence
- Repellent efficacy of 20 essential oils on Aedes aegypti mosquitoes and Ixodes scapularis ticks in contact-repellency assays2023LabWell-supported evidence
A New Mexico State University lab put 20 minimum-risk repellent ingredients through the same test at the same 10% strength, so the oils could be compared head to head instead of across studies that each used different doses and methods. The point was a like-for-like ranking of how long each one keeps Aedes aegypti mosquitoes and blacklegged ticks off skin.
Products using it
Badger
Anti-Tick Spray
Thyme oil 1.0% · Geraniol 4.5%
Complete protection
Badger
Anti-Bug Shake & Spray
Castor oil 10% · Cedarwood oil 2%
Complete protection
Badger
Bug Repellent Balm Tin
Castor oil 10% · Cedarwood oil 2%
Complete protection
Quantum Health
Buzz Away Insect Repellent
Citronella oil 5%
Complete protection
Murphy's Naturals
Mosquito Repellent Balm Stick
Castor oil 10.5% · Cedarwood oil 2.0%
Complete protection
Not recommended
Formula not fully disclosed +1 more
Quitch
Geraniol Bug Repellent Balm
Castor oil · Cedarwood oil
Complete protection
Not recommended
Formula not fully disclosed +1 more
Buzzie
Insect Repellent Spray
Cedarwood oil · Rosemary oil
Complete protection
Not recommended
Formula not fully disclosed +1 more
Skeem Design
Skeem Verbena Aura Citronella Body Spray
Citronella oil · Lemongrass oil
Complete protection
Not recommended
Formula not fully disclosed +1 more
Cliganic
Cliganic Mosquito Repellent Stick
Castor oil · Cedarwood oil
Complete protection
Regulatory notes
Source: EPA minimum risk approved inert ingredients list (placeholder import).