Menschen fuer Menschen, or People for People, said Boehm was airlifted to a hospital in Salzburg after sustaining serious injuries when the car he was riding in collided head-on Wednesday with another vehicle on a sharp corner in the southeast of the Horn of Africa country.
Boehm, 79, suffered serious bruises over his chest and back, the foundation said in a statement. It said German Chancellor Angela Merkel met briefly with Boehm at the airport in Addis Ababa, where she was on a tour of Africa.
Last month, Boehm won Italy's prestigious Balzan Prize for Humanity, Peace and Brotherhood for a lifetime of work helping impoverished Ethiopians and others. The prize is worth 2 million Swiss francs (about US$1.65 million, EUR1.2 million).
Boehm is known for his strident calls for debt forgiveness and for more trade with African nations to help their people escape abject poverty.