“Everything is poisonous, nothing is poisonous: it is all a matter of dose,” Claude Bernard stated, echoing Paracelsus’ long-ago dictum, often repeated in paraphrase as “Sola dosis facit venenum [only dose makes the poison].” Since then, finding the right dose for a drug has become one of the cornerstones of pharmaceutical research, and it currently represents the main purpose of phase I and phase II clinical trials. Modern research attempts to find the right drug at the right dose to be given at the right moment to the right patient with a particular disorder.