Random Riddle: A Poisonous Matter in the Pub

In the beginning, nobody will object
That I am the matter, issue, and subject

Change the third, then I become
Poisonous, hazardous, even fatal, to some

Change it again and then you’ll find me
In the bars and pubs of the city

What am I?
 

Random Riddle: A Poisonous Matter in the Pub