"In the Middle Ages, Ivy (Hedera helix) formed part of the 'soporific sponge,' a foul mixture of hemlock, mandrake, poppy, lettuce and other herbs, poured onto a sponge and held under the patient's nose as an anesthetic. The victim could not have failed to pass out after sniffing such a combination of evil smells." -Francesco Bianchini, Health Plants of the World: Atlas of Medicinal Plants
Ivy is fine until it has to be eradicated, and don't get me started about poison ivy. Fortunately, my work with ivy these days is limited to pots or floral arrangements - no tugging, no tears.