He did not have an easy start as the family businesses were failing, but prospecting of tin and diversification into rubber, property investment, remittances and banking brought him a greater fortune.

By the early 1910s, Eu Tong Sen expanded the family's TCM business to other parts of Malaya, Singapore, Hong Kong and Southern China.

In 2016, a consortium led by The Eu Family, Temasek Holdings and Tower Capital Asia became the majority owner to invigorate the business, and brought it delisted from SGX.

[3] As of 2022, Eu Yan Sang has 200 wholly owned "Traditional Chinese Medicine" retail outlets and clinics in Singapore, Malaysia, Hong Kong, and Macau.

The company also conducts continuous research collaborations with tertiary institutes from Singapore, Hong Kong and China to validate, develop and improve TCM products and treatments.

Eu Yan Sang has a distribution network of 170 retail outlets in China, Singapore, Malaysia, Hong Kong and Macau.

[5] Some Eu Yan Sang products are also distributed in drugstores, pharmacies, medical halls, supermarkets, petrol kiosks, airport shops, selected in-flight stores, online marketplaces.

Eu Yan Sang's manufacturing facilities in Malaysia is operated by a wholly owned subsidiary company, Weng Li Sdn Bhd.