Captain Smith?s ??Ivie?? was well known to his Powhatan Indian neighbors. For centuries, they and other Native Americans had used it for medicine. Navajos made arrow poison from this native plant, and California?s Miwoks made theWestern version, it-tum in their language, into black dye for baskets (Balls, 1962). They were very aware of its harmful character?in Mexico, it was called mala mujer, the wicked woman?but to unary European settlers, the attractive weeds became familiar as ??poison ivy?? and ??poison oak.?? With the latter blanketing the Pacific Coast and the former growing rampant over much of the rest of the continent, the two species were to become our nation?s best-known toxic plants. Contrary to popular belief, Native Americans were just as susceptible to the poisons, and as fearful of them, as those whose skins were white or brown. The lingering notion that blacks and Asians also were immune proved equally incorrect, and at least two-thirds of our country?s inhabitants, regardless of race or color, remain sensitive today to ??the poysoned weede.?? Of course, poison ivy and poison oak are not the only offenders. Literally thousands of other plant species or their products are known to damage human skin, and the most important and frequently encountered of them are the subject of this book.