Does anyone know of a natural supplement to take for hot flashes?

I had a hysterectomy in July, and I have really been having trouble sleeping, and a lot of problems with hot flashes. Does anyone know of a natural supplement that would help? I take medication for high blood pressure, so black co hash, is out of the question, along with ginseng, etc. I also cannot sleep, at all. I lay awake all night long, eyes wide open. Any suggestions would be greatly appreciated. Thanks