A commercially black hair dye widely used in Upper Egypt, traditionally known as “stone hair dye” was orally administered in different doses to four groups of albino rats. The clinical manifestations were observed and the light microscopical examination of the H&E sections of the vital organs was done. Most of the body organs showed severe congestion and lymphocytic infiltration. The results revealed that the target organs of P-phenylenediamine (PPD) were the liver and kidneys. The histological changes of the liver revealed severe vascular congestion of the blood sinusoids so that hepatocytes appeared smaller in comparison to those of the control liver. The hepatocytes showed vacuolated cytoplasm and irregular deeply stained nuclei. The kidney showed destruction of the renal tubules, congestion of the glomerular capillaries and narrowing of the filtration spaces. The cardiac muscle cells showed deeply stained nuclei and the muscle fibers were separated by wide spaces. The present study reveals the presence of a dose- effect relationship, the larger the dose; the earlier and more severe the effects. The study recommends that the sale and use of PPD containing dyes and henna should be prohibited. Certification and licensing program for cosmetics should be developed. The label should contain information about the ingredients, the manufacturer, the hazards and side effects of accidental exposure or misuse and the first aid measurements. Also it is essential to keep cosmetics and other chemicals away from the reach of children.