labeled as such. This is never a problem for patients if they are told the truth, but is a problem for some doctors who are not familiar with it. Acanthosis nigricans is a very serious, almost cancer-like condition. Parsons correctly called the increased skin pigmentation a skin change which resembles acanthosis nigricans. The similarity is only in color, not in pathology. The browning effect of niacin on a very few subjects is entirely different. It is transient, usually lasting only a few months, and when it clears the skin is perfectly normal; like an old tan, it washes off if the skin is rubbed when moist. It never recurs even with continued use. I think it is due to the deposition of melanin-containing indoles from tyrosine and adrenalin. It occurs most commonly in schizophrenic patients and is part of the healing process.