Mistletoe the leaves and berries of the plant, with teas prepared from the plant being particularly dangerous. While adults may suffer little effect, these are more pronounced in small children and in animals. There are 1500 species of Mistletoe, varying widely in toxicity; the European Mistletoe ("Viscum Album") is more toxic than the American Mistletoe ("Phoradendron serotinum"), though concerns regarding toxicity are more prevalent in the US. Mistletoe has been used historically in medicine for its supposed value in treating arthritis, high blood pressure, epilepsy and infertility: Conversely, it can cause vasoconstriction and bradycardia, and is also used as an illegal
What Is and What Should Never Be and What Should Never Be" was performed live at Led Zeppelin concerts between 1969 and 1973. A live version taken from a performance at the Royal Albert Hall in 1970 can be seen on the "Led Zeppelin DVD". Another was included on disc two of the live triple album "How The West Was Won". Two more versions were included in BBC Sessions. What Is and What Should Never Be "What Is and What Should Never Be" is a song by English rock band Led Zeppelin. It was written by Jimmy Page and Robert Plant and was included as the second