Hello and thank you for the question. I have not been asked this before, but generally, there are no studies to make this claim. You should avoid aspirin and motrin since blood thinners will increase the risk of bleeding and bruising. If you are taking any blood thinners ( coumadin, xarelto, aspirin rx by your md ) You should consult with him/ her to make sure you can do this safely. Anecdotally, there are reports about risk of gingo biloba, ginseng, and other herbals to avoid. One interesting observation, is that when patients do botox on an EMPTY stomach, the incidence of post injection nausea is higher. So make sure you don't come to the office on an empty stomach!Best to you