It is the dose, not the nature of a substance, that makes it a poison: the idea comes from Paracelsus, often called the father of toxicology. In 1993 Switzerland marked the 500th anniversary of his birth with a silver 20 francs, the third coin in the series of commemorative twenty-franc pieces begun in 1991.

The physician’s real name was Theophrastus Bombast von Hohenheim. He was born on 10 November 1493 in Einsiedeln, in today’s canton of Schwyz, and died on 24 September 1541 in Salzburg. The pseudonym is read in different ways: as a Latinisation of Hohenheim (celsus means «high») or as a challenge to the Roman physician Celsus, «surpassing Celsus». Paracelsus placed observation and chemical remedies above the authority of Galen and so changed medical practice.

The coin was designed by the Bern artist Heinz Jost. The reverse shows the head of Paracelsus, slightly turned, with «PARACELSUS» and the dates «1493-1541», and the signature «Jost» at the neck truncation. The obverse carries «FR 20», «CONFŒDERATIO HELVETICA», the year and the mint mark B. The edge bears the Latin motto «DOMINUS PROVIDEBIT», «The Lord will provide».

According to Swissmint, 260,000 uncirculated pieces and 30,000 proofs were struck. In a collection the coin sits where two themes meet: Swiss commemorative twenty-franc pieces and coins devoted to medicine and scientists.

Grade UNC: the coin has not been in circulation, shows no wear and keeps its mint lustre; only minor storage marks are possible.

Numismatics begins with a single coin and continues in the VPcoins catalogue.