The Castor Bean seeds' toxic compound Ricin, not being water soluble, is not in Castor Oil; unless due to production cross contamination. From USA National Institute of Health (1992) (= NIH pub 92-3131) regarding castor oil: * human toxicity = 1-2 pints orally of undiluted castor oil * human hyper-sensitivity possible = angiodema, asthma, rhinitis & scalatiniform rash in oil production workers * 10% castor oil dietary component fed experimental rats conclusion = no toxicity to any specific organ, organ systems or tissue; ie: no histo-pathological lesions & no hepato-toxicity from Castor oil * Ricinoleic acid is +/- 87% of Castor bean oil = a fatty acid liberated in small intestine by lipase enzyme & it is poorly metabolized, so residues linger in G-I tract * effects of Ricinoleic acid = inhibition of water & electrolyte absorption, stimulates water secretion into large intestine lumen & depresses small intestine contractions

My husband, and I live on 20 acres 11 miles outside of Bend OR. Voles have destroyed our lawn my husband has flooded the holes w/water, he's loosened them, he even started shooting them with his 410 shot gun. I started a butterfly/hummingbird garden last year, and everyday I'd go out to work, and they had feasted the night before. I bought just regular Castor Oil (consumable by humans) I put it into a sprayer, diluted it just enough so it wouldn't clog, and went out and sprayed the plants in my garden. It's only been a couple of days, and so far I haven't seen any. I even poured pure Castor Oil around the base of the plants. My husband is going to spray out lawn, and I suggested that we pour undiluted Castor Oil into the holes. We don't have a lot of lawn around our house, just enough to enjoy. I'll keep you posted. I'm going to be starting my veggie garden soon, and I'm goings to use the same process. I hope this helped !

I was gonna sugest getting a cat too. We had a small cat colony (maybe 5 total) living in my back yard till this winter when my hearless wife trapped all of them and sent them away. I'm now starting to see more chipmunks, rabbits and other animals that screw with my garden. I have 5 Peonies and 3 of them bloomed great this year, the other 2 didn't again for the 3rd year now. I forget what they even look like.

Okay. This is spring of 2016 in CO (got hit with some snow storms already). Anyway, I had vole infestation in 2014-2015 winter. I noticed the google maps of streets (runways) on my backyard in Spring of 2015 after snow cover had disappeared on my north facing backyard. Thought that some pipes had burst, only to see a small pipe running around in the runway. Then I found out what a vole was. Being softy and all, I didn't want to kill them. So I happened on this webpage and waited for Fall 2015. I applied castor oil (from laxatives at walmart) along with dish soap, 2-3 times on a weekly basis. Hoping that these critters would go away and I'll have a good lawn in 2016 spring. Here we are. 2016 spring and I have more runways than last year. So it definitely didn't work for me. I'm gonna man up and Kaput the heck out of these guys in fall 2016 now. These guys need to die.