Can I take Dandelion Root capsules to stave off extra water retention (long term) with a TT?

Congratulations on your upcoming surgery!  This question needs to discussed with your surgeon as he/she will be ultimately responsible for your care.  You will likely find that your plastic surgeon will have a list of "do's and don'ts" including medications and herbs to avoid. Best wishes for an outcome that you will be very pleased with.

Dear sherrybp4,every plastic surgeon has his own postoperative protocol which he recommends to his patients. I would suggest you to discuss this with your plastic surgeon.Daniel Barrett, MD, MHA, MS 
Certified, American Board of Plastic Surgery  
Member, Am. Society of Plastic Surgery

It is not a good idea to take unregulated supplements prior to surgery. Some may cause blood thinning or have other effects that could be detrimental to your surgery. You are best to review this with your surgeon.