What kinda poison did they use...

I don't think this is the way to answer that question. But the other one that kill Charles IX is commented in the movie.

It is not a proven historical fact that Charles X was poisoned. That was just a thing from Dumas' romance novel.

If I remember correctly (I read Dumas' novel when I was 12 or 13) the poison said to have been used was arsenic?










Snobbery is a form of romanticism, the chastity of the perfectionist

It could have been laced with a heavy concentration of strychnine, as lips are gorged with blood vessels.

Yes Charlotte de Sauve. It seemed like Strychnine but as I said that would be too quick, but I think if they had done the scene realistically she would have vomited first then breaking down to the ground convulsing and foaming from the mouth....