The patient was first admitted to the emergency ward at Enköping Hospital on Friday, before being transferred to the clinic for infectious diseases at Uppsala University Hospital, said health officials. The infection has not yet been confirmed.
According to local media reports, citing the authorities in Uppsala, three weeks ago, the patient returned from a trip, one of the points of which was the African state of Burundi.
Medical director for Uppsala Region Mikael Kohler said that the patient arrived "throwing up blood and had bloody stools", normally a symptom of Ebola.
"Other diseases are quite possible", said a statement from medical authorities there. And although Burundi is not known to have any active Ebola and the man mostly visited the urban areas of Burundi, authorities had to take the necessary precautions.
The Swedish man who sparked fears of Ebola after vomiting blood has tested negative for the deadly disease.
The highly contagious Ebola virus causes a violent hemorrhagic fever, accompanied by vomiting, diarrhea, internal and external bleeding.
The epidemic in a volatile part of Congo is the second worst ever, according to the World Health Organization (WHO). The virus is not transmitted through the air.
Staf caring for the patient are using protective clothing and have special ebola training.