I don't know of any scientific studies that support or debunk this idea but I can give you my experience with moles.

I had a serious problem with moles, tunnels everywhere in the lawn and flower beds. I sprayed the castor oil mole repellant as directed (note, the directions are VERY important since it must get to the level the moles are traveling through) and within a couple of weeks I didn't have any moles left. Now I can't say for sure it was the castor oil but if not, then the timing was certainly good! It doesn't harm the critters but is supposed to be unpleasant enough that they will go elsewhere to forage for food.

Good luck. I would say it's worth a try.

Sandy

My neighbors on both sides of me have mole trails all over their yards----I plant several Caster Bean Plants in my garden, and have no moles come into my yard---there has to be something to it.........