There are several good hospitals in Bangkok. I have been to Bumrungrad many many times (my wife has hepatitis and she needed to have tests and medication). One of my friends had vasectomy reversal and was very happy with the price and outcome. Bumrungrad is Asia's first JClA (Joint Commission International Accreditation) accredited hospital (US standards).
If you are planning to have cosmetic surgery, you might want to look at
Yanhee Hospital (JCI Accredited)
454 Charansanitwong Rd, Bang-o, Bangplad, Bangkok 10700 THAILAND
Several others for cosmetic/non-cosmetic procedures are:
BNH (Bangkok Nursing Home) Hospital (JCI Accredited)
9/1 Convent Road, Silom
Samitivej Hospital (JCI Accredited)
Chulalongkorn Memorial Hospital
1873 Rama IV Road, Pathum Wan, Bangkok, Thailand
Me Not afraid of threats from ancient trolls, thieves and liars with artificial knees.
Queen's garden bet you can remember where you got that answer. hahaha