Short term down-sides of excessive alcohol consumption are vulnerability to accidents or harm, involvement in crime, risky behaviour, risks of pregnancies and Sexually Transmitted Infections, weight-gain, dehydration and poor sleep.
In the longer term, drinking too much alcohol can harm your physical and mental health, also. As well as affecting your weight, looks and sleep, heavy drinking can lead to a wide range of serious conditions including high blood pressure, liver disease, strokes, cancers and brain damage.