- Samyang Holdings Corporation
- Sandoz
- Sang Thai
- Sanofi Consumer Healthcare
- Sanofi Pasteur
- Sanofi-Aventis
- Santen
- Schumit
- SciClone
- SciGen
- Seng Thai
- Servier
- Shanghai Sine Yanan
- Shenyang Sunshine Pharmaceutical
- Siam Bheasach
- Siam Bioscience
- Siam Pharmaceutical
- Sinovac Biotech
- SK Bioscience
- SK Plasma
- Softgel Healthcare
- SPB Pharma
- SPS Medical
- Sriprasit Dispensary
- Sriprasit Pharma
- ST Pharmetics
- Stada
- Stellapharm
- Stragen
- Sun Pharma
- Swiss Parenterals
- Symgens
- Synthon