One person was killed and 44 were injured early Sunday when their long-distance bus swerved and hit a wall on a motorway near Zurich, police said.
Three people were severely injured.
The bus was en route from the Italian city of Genoa to Dusseldorf in Germany, according to investigators.
"We know that there was no child among the injured, and that no children were in the bus," police spokeswoman Rebecca Tilen told Swiss news portal 20 Minuten.
According to Tilen, the bus was operated by a subcontractor of Flixbus, a German company that offers intercity services.
A police spokesman contacted by dpa said there was no further information to share on the identities of the victims so far.