text: By the 1930s, several large classes of natural products were known. Important milestones included:
  * Terpenes, first systematically studied by Otto Wallach (Nobel Prize 1910) and later by Leopold Ružička (Nobel Prize 1939)
  * Dyes based on porphins (including chlorophyll and heme), studied by Richard Willstätter (Nobel Prize 1915) and Hans Fischer (Nobel Prize 1930)
  * Steroids, studied by Heinrich Otto Wieland (Nobel Prize 1927) and Adolf Windaus (Nobel Prize 1928)
  * Carotenoids, studied by Paul Karrer (Nobel Prize 1937)
  * Vitamins, studied among others by Paul Karrer, Adolf Windaus, Robert R. Williams, Norman Haworth (Nobel Prize 1937), Richard Kuhn (Nobel Prize 1938) and Albert Szent-Györgyi
  * Hormones studied by Adolf Butenandt (Nobel Prize 1939) and Edward Calvin Kendall (Nobel Prize 1950)
  * Alkaloids and anthocyanins, studied by, among others, Robert Robinson (Nobel Prize 1947)