["Dosis solum facit venenum" also for herbal products].

A report of severe hepatitis due to the use of material from the plant Chelidonium majus, reminds us that herbal products can be much more life-threatening than many people realise. The widespread use of plants for food has reinforced the idea that eating plants promotes health. With the development of organic chemistry in the 19th century it became possible for the first time to purify and identify pharmacologically active plant constituents and later on to synthesize related compounds with an even stronger activity.

Bioassays in whole animals.

The basis for whole animal bioassays as practised today was laid down by Paul Ehrlich in 1894. He introduced the concepts of a stable standard preparation and of the unit of activity as the activity of a defined mass of that standard preparation in the assay performed. Such assays have often provided a way of quantifying newly discovered active principles of biological origin, so that they could be applied in clinical medicine.