Is all alcohol haram or just ethanol which is used in alcoholic beverages? Let's say a medicine contains alcohol but it's not ethanol.
As a general Islamic rule (www.Islamquest.net) all kinds of drinks which are considered as intoxicant drink, are haram.
Those kinds of Alcohols such as ethanol and methanol which essentially are considered as poisonous matters and are not drinkable, are clean (not Najis) and are not considered as haram drinks till the time that they have not changed to the diluted drinks (and not to be alcoholic liquor or intoxicant). (Of course from another aspect we have to notice that whatever is harmful for the body, totally is counted as haram practice).
As more related info. it is profitable to read the view of Grand Ayatollah Khamenei as well. According to his ruling: intoxicant drinks are haram (precautionary). Generally speaking, the alcohol which is not determined whether or not it is originally intoxicating or not, is ritually clean and is treated as such.
Accordingly as @Ansari mentioned, drinking intoxicates drinks is considered as an impermissible practice.