Valtonen used to run fairly thorough testing to exclude other illnesses, especially infections, immune deficiencies and common autoimmune causes, as well as running imaging studies. Almost every CFS/ME patient was recommended to take prednisone and doxycycline. Some were also given IVIG and valaciclovir. Valtonen is also known for treating chronic Lyme disease, mold illness and multiple chemical sensitivity and discussing those subjects in the media.
Peculiarly, based on his 2015 presentation at a Finnish sleep medicine seminar, Valtonen believes that taking walks outside in "fresh air" is a good treatment for CFS/ME and that CFS/ME often spontaneously remits. The walks may indeed be a good recommendation for some of the mold/MCS patients that he treats, but not for CFS/ME.
After his retirement Ville Valtonen has regularly produced scathing commentary in interviews about the sorry state of disability benefits in Finland. Tens of thousands of disabled peple are unable to get benefits because their diagnosis (such as CFS/ME or mold illness) is not accepted.
Valtonen caused a small scandal with the comments he made in a documentary film about mold illness called Kanarialinnut (The Canaries), which was aired by the Finnish national broadcasting company Yle. He referred to insurance doctors as scum and when asked how they should be dealt with, he dryly suggested they could be shot. This comment was censored from the film after its TV premiere, when it was made available for watching on the broadcasting company's website.