roaches poison? got such thing meh?
rat poison i know lar..

Anyway u can try the ridsect cockroaches trap....
can found at any departmental store....

Btw few weeks ago i was eating bread in my car...
Bought whole loaf but cant finish...after 1 hour like that i hear some sounds...then i saw the cockroaches already went inside the bread...
So i grab the plastic and throw out...still left like 1/4 of the bread loaf wasted...