Professor Bo Holmstedt was a prominent toxicologist both nationally and internationally, well-known in the toxicology community for his outstanding research, engagement in education, contributions to toxicological organisations and role as a leading authority in toxicological evaluation. He covered wide ranges, geographically, scientifically, culturally and intellectually.

He was born 1918 in the southern part of Sweden, and studied medicine at the Karolinska Institute.  In 1952, he graduated with a MD PhD in pharmacology, and became a full professor in toxicology at the Karolinska Institute in 1964. He finished his academic career as head of the Toxicology Unit, Institute of Environmental Medicine at the same institute.

He was on the editorial board of many pharmacological and toxicological journals. He also was a member of many scientific societies including The Swedish Society of Toxicology, as  its first President and later as honorary member, member of the SOT (Society of Toxicology in USA), and the European Society of Toxicology, as a founding member. He held several leading positions, with the most prestigious being President from IUTOX, International Union of Toxicology (1983-1986). He published around 250 scientific papers and wrote close to 50 book chapters. For his contributions to toxicological science, he received the Merit Award both from SOT (1987) and EUROTOX (1993).

Professor Holmstedt's main field of scientific interest was mechanism of action of toxic compounds, and he received international recognition for pioneer work within several such fields. During the 1940's and 1950's he studied organophosphate compounds with cholinesterase-inhibiting actions. In his dissertation thesis, written in 1951, he described the synthesis of tabun, the well-known nerve gas with previous horrendous usage, its pharmacological effects, and atropine as its effective antidote. He used his knowledge about cholinesterases to develop a histochemical method to reveal cholinergic nerves.

During the 1960's, Holmstedt started to use gas chromatography in combination with mass spectrometry  in order to directly identify the structure of hallucinogens, drugs and their metabolites. Together with collaborators he developed a new technique, called mass fragmentography, which had a markedly improved sensitivity. This made it possible to identify and quantify endogenous compounds not detected earlier, drugs and their metabolites in body fluids. This became most appropriate during the Alpha Helix expedition to the Amazons in 1967, where he and his collaborators identified hallucinogens, 5-metoxy-N, -carboline-alkaloids, used by different South and American Indian tribes. A similar finding was the identification of “hog”, a product abused in USA, as 1-(1-phenylcyclohexyl) piperidine and the finding of cannabinol in marijuana smokers.

It is evident from this very short summary that Bo Holmstedt contributed to many key areas of pharmacology and toxicology in a constructive and interdisciplinary way. He saw the importance of toxicology as an important medical discipline and worked relentlessly to obtain its recognition in science, education and chemical regulation, both nationally and internationally. Today, many toxicologists are grateful to his contributions to the development of toxicology. Professor Bo Holmstedt was a true scientist, knowledgeable and critical in detail, without losing the overview.