A 14th Century Poisoning – what was used?

"Stephen Segrave was Constable of the Tower ofLondon in August 1323 during the escape of Roger Mortimer, whowould eventually overthrow Edward II (in conjunction with Edward’swife, Queen Isabella) ... The deputyconstable of the Tower in August 1323 was a man called GerardAlspaye and it was he who aided in the sedation of Segrave and theother …