JUNIPER PUBLISHERS-OPEN ACCESS JOURNAL OF PHARMACY & PHARMACEUTICAL SCIENCES          Introduction   Paracelsus, the medieval physician, who is often  viewed as the father of modern toxicology, was the first person to  appreciate that "the dose makes the poison". This essentially means that  very toxic materials can be used therapeutically at very low  concentrations and conversely even safe materials can be toxic if  overdosed. This in turn led to Haber's law, which basically states that,  the incidence and/or severity of any toxic effect is dependent on the  total exposure to the toxic agent; that is, the exposure concentration  (c) rate(or dose) multiplied by the duration time (t) of exposure (i.e.  cxt). This law is often utilised in setting exposure limits for toxic  components. The major caveat, is that establishing acceptable daily  intakes (ADIs) for long-term exposures to a toxic substance when only  data from short-term studies are available, does require...