كتب : Omar AbdelAziz
The Croatian accused club doctor Gotz Dimanski and cardiologist Manju Guha of giving him wrong diagnosis, which forced him to have a kidney transplant last year.
"If the doctors had treated me correctly then things would have gone differently" Klasnic said.
"The people who have created this mess will have to pay. Enough is enough now, the truth must come out.
"I will never allow Dr Dimanski to treat me ever again."
Daily Bild reported that the 28-year-old, who has fully recovered, demands around €1.4M as compensation.
Klasnic made 12 appearances for Bremen this season, scoring six times.