The production of bile pigments by mammalian metabolism and by biosynthesis in plants compares with the annual production figures of prominent organic chemicals. For example, the daily degradation of hemoglobin in humans yields about fourhundred milligrams of bile pigments per person . This amounts to about twohundredthousand tons per year calculated for the present world population — the annual industrial production of toluene in the FRG (1980) was 260,596 tons . Although unnoticed by the majority of us, these pigments become important for many people in case of metabolic diseases like pigment gall stones or neonatal jaundice. Also they are of paramount importance as the antenna pigments Phycoerythrobilin and Phycocyanobilin in the course of photosynthesis in certain algae where they funnel singlet energy into a reaction center containing chlorophyll. Moreover, the sensory system Phytochrome, which governs photomorphogenesis in the plant kingdom contains a bile pigment as the chromophoric unit.