Relative to some other AS like winny, its not as bad on the ol' liver, but it still adds more stress. As with anything -- moderation is the key. It seems like for the cost & effort of doing a cycle, it would be optimal to do the whole thing right and get the most out of it. A few drinks doesn't hurt - but lots is just totally stressing your body, extra carbs -> nice insulin spike, etc.
You might do a search on the topic of drinking on a cycle or cruise the AS board -- I've seen it discussed.