I once heard that a mixture of sugar and baking soda is effective against rodents, as they can't burp or fart. This is only hearsay as I didn't actually test it myself (that is to say, I didn't personally feed it to a mouse and watch the results, nor have I observed mice to determine whether they can perform said gaseous expulsions), but it was used on a horse ranch I worked at and there did not seem to be a rodent problem. Somebody wanta try it and report back? I have cats, so rodents aren't a problem here either, nor are lice or mites.