In Hahnemann's Materia Medica Pura ; American Homoeopathic Review , Vol. I ; Hughes' Pharmacodynamics . What is Rhus tox. ? It is the common three-leaved poison Ivy , the middle leaf being stalked. What part is used, when gathered and how is the tincture prepared ? The fresh leaves collected after sunset on cloudy, sultry days from shady places, in May and June before the period of flowering. The tincture is prepared in the same manner as that of Gelsemium . It is of dark brown color, of biting and astringent taste and strong acid reaction. What are some other varieties of Rhus ? Rhus radicans , which is the same as Rhus tox ., being a creeping variety clinging to trees. Rhus glabra , or the common Sumach , less poisonous. Rhus venenata , very poisonous and large, growing in swamps, Poison Elder , or Swamp Dogwood . Leaves 5 to 12 inches long with 6 to 13 leaflets. Rhus diversiloba , or Californica , or the Poison Oak . Rhus aromatica , an aromatic species. Distinguished from Rhus tox ., by red berries. Is non-poisonous, useful in enuresis. What are the characteristics of the whole family ? They all produce an intense irritation of the skin, from mere itching redness to erysipelatous inflammation, with vesicles and pustules. Mention five drugs which antidote the poison of the Rhus.