Dr Suchai returned to Thailand in August 1985 to take the position of Chest Physician and Lecturer at Siriraj Medical School, Mahidol University.

The breadth of researches, editorials, and book chapters that he contributed in this time is evidenced by the range of publications that came out with an outstanding reputation, so he was promoted to Professor of Medicine in 1996 when he was 41 years old.

[4][failed verification] Professor Suchai pursued his clinical and research interests in asthma, COPD, and tuberculosis.

[5][6] He wrote chapters on international textbooks such as Om P.Sharma, ed., Lung Diseases in the Tropics (New York: Marcel Dekker, 1991).

He served alongside four other delegates holding the title of vice president, whose nationalities included New Zealand, Uruguay, the United Arab Emirates, and the State of Eritrea.

[13][14][15] He organized and chaired a very successful International Partnership on Avian and Pandemic Influenza Meeting on 10 October 2005 at the United Nation Conference Centre in Bangkok to seek their collaboration in preparing for the anticipated public health emergency linked to the H5N1 strain of the disease.

[22][23][24] As Deputy Prime Minister, Professor Suchai represented the Thai Government to give a speech at the UN General Assembly Special Session on HIV/AIDS held in New York on 30 May 2006.

The Heads of State and Government were invited to give a speech to declare their commitment to addressing the crisis through action.