The possibility of sensitization to emanations from individual human beings has been suggested in the past but, so far as we have been able to discover, no clearly authentic case of this type has been reported. Over quite a period of time, one of us included tests for sensitization to human hair in the routine sensitization studies. When, after several hundred such tests, it was found that no case had given a positive reaction, the use of this allergen was discontinued. One young woman with dermatitis from allergy to silk found that each time she had her hair trimmed the dermatitis over her neck and shoulders flared up. She was sensitive by scratch test neither to stock human hair nor to an extract of her own hair. A patch test with her own hair was negative. No special washes or other treatment of the hair was used at these times.