Sorry i reply after so much time has passed. I have got fish prazi from ebay too without additives. I have to tell you that you were not sick because of the prazi itself but because it has killed something. You get sick because the worms die and they release toxins. You got good prazi then. You need to be aware of this for next time. Please see the proper dosing guidelines and what to do if you get sick (=get die off) in this document: