Personally I think 'anything' is too restrictive. I had stevia while on MC, combined Master-Cleanse with oxygene therapies, etc. Don't think it's a problem in any way.
But alcohol, yeah, don't even think about it. Your organism won't be able to handle it. If you've been fasting for many days I won't be surprised if you end up in emergency room. Wait at least a few days after you start eating food again.