Of course it is a relapse. I knew a guy in treatment and subsequently a half-way house. He was a really nice guy. He started smelling very strong of mouthwash. Finally, we found out that he had been drinking mass quantities of Listerine. He was buying it by the case. Thing is I am sure that in his mind he had convinced himself that he was not relapsing and this was not considered drinking. Otherwise why not just drink, right? Alcohol addiction at the basic level is a very crazy thing. There are many shades and delusions associated with the addiction and this is just another example.