Goischke HK - Via a single-blind study, the authors intended to study the therapeutic effectiveness of add-on therapy of vitamin D (VD) and to determine its effective doses for the maintenance of functional and social independence in patients with multiple sclerosis (MS). As there were evidences recorded that VD deficiency has a correlation with brain atrophy, recognition of VD as a “multipurpose steroid hormone” could also be used to maintain cognitive function and prevent premature possible dementia. Hence, it was concluded that vitamin D add-on therapy would be an almost unproblematic and most likely to be accepted by patients with MS.