If you are HIV+, remember that lots of alcohol makes HIV worse. Alcohol can also interact very badly with ARVs (HIV medication). Drink small amounts of alcohol or don't drink it at all. Also alcohol is bad for your liver. Most medicines are broken down in the liver so you don't want anything to damage your liver. This is important if you're on ARVs.
Alcohol also stimulates your libido (makes you want to have sex) and can make you lose control. Always be prepared to only have safe sex (make sure you have condoms available)! Being drunk also diminishes your ability to use a condom.