If you're having a party in your home bar you might be liable for injuries if a person gets drunk, leaves and has an alcohol-related accident. This liability stems from what is known as "Social Host Liability Laws." Not every state has this law on the books and the states that do judge it by different standards of host liability.
Let's say: Debbie goes to Bob's house for a party and gets bombed. She leaves and runs into Joe's car. In every state Joe would be able to bring a personal injury case against Debbie over the car accident and any injuries. IF, the state as a "Social Host Liability Law", Joe might also be able to make a civil claim against Bob.
In some states, Bob would only be liable if he broke the law: say, if Debbie is underage. In other states Bob might be liable if he "knew or should have known" that Debbie was drunk and if Bob knew she would be driving a vehicle.
Not every state has "Social Host Liability Laws" and some states have laws that specifically shield the social host from civil liability if a guest drinks and causes an accident.
Can a drunk guest sue you if you they have an accident?
According to Nolo.com, a legal self-help website, the answer here is almost always no. Even in states that have fairly liberal “social host” laws, liability usually only extends to third parties who are harmed by the intoxicated guest’s conduct. A “first party” claim by the intoxicated guest will almost always fail. One notable exception is where a host provides alcohol to a minor. In that situation, a minor who is injured in an alcohol-related accident (even one they themselves caused) may be able to file a lawsuit against the host.