
I'd suggest that this is only going to be a 'band aid' solution. Far better would be to get to the root of what's causing all this upset and fact is not all dogs are suited to a raw diet in my opinion and with respect to those who suggest otherwise. And a raw diet has to be a properly balanced raw diet. With our first hound, we fed raw breast of lamb and offal and 'terrier meal' - very much back in the day and not at a time when people went to raw-feeding by any means. As our numbers increased and my time not as available as before (to be making up a properly balanced raw diet), I switched to using a good quality, meat or fish-based complete food, you may find this suits your particular dog better. In the UK, Arden Grange's Sensitive, which is fish and potato, has sorted out the residual problems we had with a hound we bought in, coming to us with Giardia at 4 months. I did try switching him recently to Pooch & Co's lamb and rice but after a few months, his skin started reacting so it was back to AG Sensitive.
Vomiting bile and grabbing at grass would suggest an irritated digestive system/empty tummy and clearly although Milk of Magnesia might help in the short term, it's not going to be a long-term solution, I'd suggest.