Rothman and his co-workers1 showed that with the onset of puberty in children the sebaceous glands of the scalp start to secrete a sebum which contains, in higher concentrations than before puberty, saturated fatty acids of a low boiling point with selective fungistatic and fungicidal action on Microsporon audouini. I conceived the idea that the oral administration of one of the saturated or unsaturated fatty acids might be therapeutically effective in the treatment of tinea capitis (M. audouini). I have not found in the literature any reference to the oral administration of a pure saturated or unsaturated fatty acid.
In cases of tinea capitis it was decided to start first with undecylenic acid, because it was most easily obtainable. Toxicity tests were done on rabbits, mice and guinea pigs, and the acid was found relatively nontoxic. The acid was put up in capsules and perles (usually 0.5 Gm. each).
PERLMAN HH. UNDECYLENIC ACID GIVEN ORALLY IN PSORIASIS AND NEURODERMATITISA Preliminary Report. JAMA. 1949;139(7):444-447. doi:10.1001/jama.1949.02900240022005