I've read that its specifically Sunflower oil or Seasame oil to be used for oil pulling..but I guess safflower might as well work too?. I've had PND.. but I put it up to the fact of stressed and eating a lot of yogart at the time. The PND stopped a lot once once I started eating better quality brand of yogart; and not having it as often. At the moment, I have a slight bit of PND..no dairy..slept enough..(though still working on the stress). But,I did OP at least 2 or 3 hrs ago..and then lunch later. I don't know if the timing counts or disqualifies the OP/PND connnection in my case. I have not connnected post nasal drip with the oil pulling...but now that you mention it I will be more aware.