The late Prof Yeoh Teow Seng was known for his passion in Pharmacology and is remembered as an excellent educator. He was noted for his gentlemanly conduct, his humility and peaceful demeanour, as well as his concern for the students under his charge. He was very much loved and respected as a teacher and mentor. Students loved his very clear and concise lectures. He had a phenomenal memory and could remember the face of every student in the class. He was universally remembered for being able to randomly call out any student by name in every class he taught. As a researcher, Prof Yeoh was known for being extremely meticulous. He authored and contributed to papers in pharmacology and toxicology. He made advances in gastrointestinal pharmacology and important early contributions to understanding the toxicity of mercury in certain Chinese Traditional Medicine formulations and the safety of dental amalgams containing mercury.