Tulp was both a surgeon and mayor of Amsterdam. As such he was responsible for inspections of apothecary shops. Thanks to new shipping routes, pharmacists in Amsterdam had access to many exotic herbs and spices from the East,  from which they made a big business in new medicines; in Tulp's time there were 66 apothecaries in Amsterdam. Shocked at the exorbitant prices asked for useless anti-plague medicines when Amsterdam was stricken by plague in 1635, Tulp gathered his physician and pharmacist colleagues to write the first Amsterdam pharmacopeia in 1636, the Pharmacopoea Amstelredamensis. To maintain sufficiently high standards, the Amsterdam Apothecary guild required an exam based on the pharmacopeia before new pharmacists could set up shop in Amsterdam. This pharmacopoeia became a standard work, and set an example for all the other cities in Holland. Digital facsimile of "Editio altera" also published in 1636 from the Internet Archive at this link.

Facsimile of the first Amsterdam pharmacopoeia, 1636, with an introduction by D.A. Wittop Koning. [Introd. translated into English by Miss C.F.L. Los]. Nieuwkoop: B. de Graaf, 1961.