Shafaqna (Shia International News Association) – The Grand Ayatollah Sistani answered some questions regarding Alcohol. According to Shafaqna the questions and answers are as follows:
Question: What is your opinion on Muslims eating in non-Muslim or even Muslim owned and operated restaurants which serve halal food however also serve alcoholic drinks? If the alcohol is not being consumed at our table, does this change the ruling?
Answer: If alcohol is not consumed at your table, there would be no objection and you can eat halal food in that restaurant. Yes, if going to such a restaurant is considered bad for the reputation of a Muslim, it is not permissible to eat in there.
Question: What is the ruling on a Muslim working in a restaurant in which he must serve alcohol to patrons of the restaurant?
Answer: It is not permissible.
Question: Alcohol is used in the production of many drugs and medications: Is it permissible to take them? Are they considered pure (tãhir)?
Answer: hey are pure; and since the alcohol used in them is so minute that it dissolves in them, it is therefore permissible to take them also.
Question: A Muslim enters a café and sits down at a table to drink tea, then a stranger comes at the same table to drink wine. Is it obligatory upon the Muslim to stop drinking tea and leave?
Answer: Yes, it is obligatory to move away from that table.
Source: Ayatollah Sistani