Immunologists have relied heavily on oil-based adjuvants to generate antibodies or induce auto-allergic responses in experimental animals. These are rarely used today for human vaccination because of their persistent irritancies and propensity to cause ulcers at sites of injection. However oily materials with adjuvant properties abound in our modern environment, both personal and extraneous. Their inadvertent impact as cryptotoxins may contribute to the rising incidence of auto-allergic diseases in recent times. Experimentally, the potential adjuvanticity of various oils, fats and other lipids can be evaluated by their ability (or otherwise) to induce auto-allergic disease(s) in rats and mice with, or even without, the addition of a mycobacterial immunostimulant. Genetic factors have been recognized that determine an animal's susceptibility or resistance to these oil-induced immunopathies. So it may be profitable to further characterize these factors, first in animals and then perhaps in human populations, to help find ways to enhance natural resistance to those adjuvant-active oils that may be widely distributed in the personal environment, notably mineral oil(s). (The six tables in this article summarize some relevant facts and a few conjectures.) A caveat: This review is restricted to the adjuvant properties of some oils in the personal environment. It does not cover the mechanisms of adjuvanticity.