Athletes were staying at the hotel during the European Athletics Championship, which ended on Sunday.
The bag containing the suspected drugs was found in a bin on Sten Sturegatan, which local media reported is close to the Hotel Opalen where many of the competitors stayed during the championships. Västra Götaland Police wrote in a statement that most of the material was used.
Police later discovered another bag, containing equipment for carrying out blood transfusions.
The contents of the bag will now be analyzed by police technicians.
Police say they currently have no suspects in their investigation.