The discussion about a connection between diabetes and psoriasis is picked up again. Serum-values of glucose, insulin and C-peptide after intravenous glucose-load and of glucose and C-peptide after intravenous insulin-load were tested. The level of insulin and C-peptide after i. v. glucose-load was found higher in psoriasis-patients (hyperinsulinism). Considering earlier investigations and new results in diabetes-research (incretin concept), a connection between the two diseases must be denied. The carbohydratemetabolism-deviation in psoriasis could be declared by an enteropathy.