A 6a-methylprednisolone derivative of the general formula:
wherein R' is a hydrogen atom or the group
where R3 is a straight or once-branched chain C1-4 alkyl group, a phenyl group or a lower alkoxy- or alkylthio-methyl group, and R2 is a straight or once-branched chain C1-4 alkyl group, a phenyl group or a lower alkoxy- or alkylthio-methyl group, with the proviso that when R2 is ethyl group, R1 is not a hydrogen atom or a propionyl group.
These compounds exhibit a strong local anti-inflammatory effect and so are useful in external anti-inflammatory preparations for the treatment of various dermal disorders and also as anti-allergic drugs for the treatment of asthma and other allergic diseases.